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path: root/drivers/block/aoe
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2012-12-18aoe: fix use after free in aoedev_by_aoeaddr()Dan Carpenter
We should return NULL on failure instead of returning a freed pointer. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: update internal version number to 81Ed Cashin
This version number is printed to the console on module initialization and is available in sysfs, which is where the userland aoe-version tool looks for it. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: identify source of runt AoE packetsEd Cashin
This change only affects experimental AoE storage networks. It modifies the console message about runt packets detected so that the AoE major and minor addresses of the AoE target that generated the runt are mentioned. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: allow comma separator in aoe_iflist valueEd Cashin
By default, the aoe driver uses any ethernet interface for AoE, but the aoe_iflist module parameter provides a convenient way to limit AoE traffic to a specific list of local network interfaces. This change allows a list to be specified using the comma character as a separator. For example, modprobe aoe aoe_iflist=eth2,eth3 Before, it was inconvenient to get the quoting right in shell scripts when setting aoe_iflist to have more than one network interface. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: allow user to disable target failure timeoutEd Cashin
With this change, the aoe driver treats the value zero as special for the aoe_deadsecs module parameter. Normally, this value specifies the number of seconds during which the driver will continue to attempt retransmits to an unresponsive AoE target. After aoe_deadsecs has elapsed, the aoe driver marks the aoe device as "down" and fails all I/O. The new meaning of an aoe_deadsecs of zero is for the driver to retransmit commands indefinitely. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: use dynamic number of remote ports for AoE storage targetEd Cashin
Many AoE targets have four or fewer network ports, but some existing storage devices have many, and the AoE protocol sets no limit. This patch allows the use of more than eight remote MAC addresses per AoE target, while reducing the amount of memory used by the aoe driver in cases where there are many AoE targets with fewer than eight MAC addresses each. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: avoid races between device destruction and discoveryEd Cashin
This change avoids a race that could result in a NULL pointer derference following a WARNing from kobject_add_internal, "don't try to register things with the same name in the same directory." The problem was found with a test that forgets and discovers an aoe device in a loop: while test ! -r /tmp/stop; do aoe-flush -a aoe-discover done The race was between aoedev_flush taking aoedevs out of the devlist, allowing a new discovery of the same AoE target to take place before the driver gets around to calling sysfs_remove_group. Fixing that one revealed another race between do_open and add_disk, and this patch avoids that, too. The fix required some care, because for flushing (forgetting) an aoedev, some of the steps must be performed under lock and some must be able to sleep. Also, for discovering a new aoedev, some steps might sleep. The check for a bad aoedev pointer remains from a time when about half of this patch was done, and it was possible for the bdev->bd_disk->private_data to become corrupted. The check should be removed eventually, but it is not expected to add significant overhead, occurring in the aoeblk_open routine. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: improve handling of misbehaving network pathsEd Cashin
An AoE target can have multiple network ports used for AoE, and in the aoe driver, those are tracked by the aoetgt struct. These changes allow the aoe driver to handle network paths, or aoetgts, that are not working well, compared to the others. Paths that do not get responses despite the retransmission of AoE commands are marked as "tainted", and non-tainted paths are preferred. Meanwhile, the aoe driver attempts to "probe" the tainted path in the background by issuing reads of LBA 0 that are padded out to full (possibly jumbo-frame) size. If the probes get responses, then the path is "redeemed", and its taint is removed. This mechanism has been shown to be helpful in transparently handling and recovering from real-world network "brown outs" in ways that the earlier "shoot the help-needing target in the head" mechanism could not. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: return real minor number for static minorsEd Cashin
The value returned by the static minor device number number allocator is the real minor number, so it must be multiplied by the supported number of partitions per aoedev. Without this fix the support for systems without udev is incomplete, and the few users of aoe on such systems will have surprising results when device nodes names do not match the AoE target. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: initialize sysminor to avoid compiler warningEd Cashin
Because the minor_get and related functions use the return values for errors, the compiler doesn't know that sysminor will always either 1) be initialized in aoedev_by_aoeaddr by the call to minor_get, or 2) be unused as the "goto out" is executed. This patch avoids the compiler warning. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: make error messages more specific in static minor allocationEd Cashin
For some special-purpose systems where udev isn't present, static allocation of minor numbers is desirable. This update distinguishes different failure scenarios, to help the user understand what went wrong. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: remove call to request handler from I/O completionEd Cashin
There is no need to call the request handler function in the I/O completion routine. The user impact of not doing it is a more "nice" aoe driver that is less susceptible to causing soft lockups. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: cleanup: correct comment for aoetgt noutEd Cashin
A misplaced comment was attached to the nout member of the aoetgt. This change corrects the comment. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: increase default cap on outstanding AoE commands in the networkEd Cashin
The aoe driver will never be waiting for more than aoe_maxout AoE commands from a given remote network port on an AoE target. Increasing the cap increases performance. Users can tighten the setting to reduce the amount of memory used for handling AoE traffic or the network bandwidth used for AoE. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: remove vestigial request queue allocationEd Cashin
Before the aoe driver was an I/O request handler, it was a make_request-style block driver. Even so, there was a problem where sysfs expected a request queue to exist, so one was provided in commit 7135a71b19be ("aoe: allocate unused request_queue for sysfs"). During the transition to the request-handler style, a patch was merged that was based on a driver without the noop queue, and the noop queue remained in place after the patch was merged, even though a new functional queue was introduced by the patch, allocated through blk_init_queue. The user impact is a memory leak proportional to the number of AoE targets discovered. This patch removes the memory leak and cleans up vestiges of the old do-nothing queue from the aoeblk_gdalloc function. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: copy fallback timing information on destination failoverEd Cashin
Commit f3b8e07af774 ("aoe: commands in retransmit queue use new destination on failure") omits the copying of the coarse-grained time when an AoE command was sent during the failover from one destination MAC address on the AoE target to another. The coarse-grained timing is only used when the system time changes or an unlikely length of time has passed since the sending of the AoE command. Users will not be impacted unless their system clock is very inaccurate or something unusual (e.g., 10 GbE link reset) happens during the period when the aoe driver is handling the failure of a port on the AoE target. Being effected will mean that an AoE target could be considered "down" too eagerly. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: update driver-internal version to 64+Ed Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: commands in retransmit queue use new destination on failureEd Cashin
When one remote MAC address isn't working as a destination for AoE commands, the frames used to track information associated with the AoE commands are moved to a new aoetgt (defined by the tuple of {AoE major, AoE minor, target MAC address}). This patch makes sure that the frames on the queue for retransmits that need to be done are updated to use the new destination, so that retransmits will be sent through a working network path. Without this change, packets on the retransmit queue will be needlessly retransmitted to the unresponsive destination MAC, possibly causing premature target failure before there's time for the retransmit timer to run again, decide to retransmit again, and finally update the destination to a working MAC address on the AoE target. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: use high-resolution RTTs with fallback to low-resEd Cashin
These changes improve the accuracy of the decision about whether it's time to retransmit an AoE command by using the microsecond-resolution gettimeofday instead of jiffies. Because the system time can jump suddenly, the decision reverts to using jiffies if the high-resolution time difference is relatively large. Otherwise the AoE targets could be considered failed inappropriately. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: manipulate aoedev network stats under lockEd Cashin
With this bugfix in place the calculation of the criterion for "lateness" is performed under lock. Without the lock, there is a chance that one of the non-atomic operations performed on the round trip time statistics could be incomplete, such that an incorrect lateness criterion would be calculated. Without this change, the effect of the bug would be rare unecessary but benign retransmissions. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: err device: include MAC addresses for unexpected responsesEd Cashin
The /dev/etherd/err character device provides low-level information about normal but sometimes interesting AoE command retransmits and "unexpected responses", i.e., responses for packets that have already been retransmitted. This change adds MAC addresses to the messages about unexpected responses, so that when they occur, it's more easy to determine the network paths to which they belong. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: improve network congestion handlingEd Cashin
The aoe driver already had some congestion handling, but it was limited in its ability to cope with the kind of congestion that can arise on more complex networks such as those involving paths through multiple ethernet switches. Some of the lessons from TCP's history of development can be applied to improving the congestion control and avoidance on AoE storage networks. These changes use familar concepts from Van Jacobson's "Congestion Avoidance and Control" paper from '88, without adding significant overhead. This patch depends on an upcoming patch that covers the failover case when AoE commands being retransmitted are transferred from one retransmit queue to another. Another upcoming patch increases the timing accuracy. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: provide ATA identify device content to user on requestEd Cashin
Make the aoe driver follow expected behavior when the user uses ioctl to get the ATA device identify information, allowing access to model, serial number, etc. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: update driver-internal version number to 60Ed Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: whitespace cleanupEd Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: cleanup: remove unused ata_scnt functionEd Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: "payload" sysfs file exports per-AoE-command data transfer sizeEd Cashin
The userland aoetools package includes an "aoe-stat" command that can display a "payload size" column when the aoe driver exports this information. Users can quickly see what amount of user data is transferred inside each AoE command on the network, network headers excluded. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: support larger I/O requests via aoe_maxsectors module paramEd Cashin
The GPFS filesystem is an example of an aoe user that requires the aoe driver to support I/O request sizes larger than the default. Most users will not need large I/O request sizes, because they would need to be split up into multiple AoE commands anyway. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: support the forgetting (flushing) of a user-specified AoE targetEd Cashin
Users sometimes want to cause the aoe driver to forget a particular previously discovered device when it is no longer online. The aoetools provide an "aoe-flush" command that users run to perform this administrative task. The changes below provide the support needed in the driver. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: update cap on outstanding commands based on config query responseEd Cashin
The ATA over Ethernet config query response contains a "buffer count" field reflecting the AoE target's capacity to buffer incoming AoE commands. By taking the current value of this field into accound, we increase performance throughput or avoid network congestion, when the value has increased or decreased, respectively. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: print warning regarding a common reason for dropped transmitsEd Cashin
Dropped transmits are not common, but when they do occur, increasing the transmit queue length often helps. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18aoe: describe the behavior of the "err" character deviceEd Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-11-23aoe: avoid running request handler on plugged queueEd Cashin
Calling the request handler directly on a plugged queue defeats the performance improvements provided by the plugging mechanism. Use the __blk_run_queue function instead of calling the request handler directly, so that we don't interfere with the block layer's ability to plug the queue. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-10-05aoe: update aoe-internal version number to 50Ed Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: remove unused codeEd Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: make dynamic block minor numbers the defaultEd Cashin
Because udev use is so widespread, making the old static mapping the default is too conservative, given the severe limitations it places on usable AoE addresses. Storage virtualization and larger shelves have made the old limitations too confining. These changes make the dynamic block device minor numbers the default, removing the limitations on usable AoE addresses. The static arrangement is still available with aoe_dyndevs=0, and the aoe-stat tool from the userland aoetools package, the user space counterpart to the aoe driver, recognizes the case where there is a mismatch between the minor number in sysfs and the minor number in a special device file. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: update and specify AoE address guards and error messagesEd Cashin
In general, specific is better when it comes to messages about AoE usage problems. Also, explicit checks for the AoE broadcast addresses are added. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: retain static block device numbers for backwards compatibilityEd Cashin
The old mapping between AoE target shelf and slot addresses and the block device minor number is retained as a backwards-compatible feature, with a new "aoe_dyndevs" module parameter available for enabling dynamic block device minor numbers. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: support more AoE addresses with dynamic block device minor numbersEd Cashin
The ATA over Ethernet protocol uses a major (shelf) and minor (slot) address to identify a particular storage target. These changes remove an artificial limitation the aoe driver imposes on the use of AoE addresses. For example, without these changes, the slot address has a maximum of 15, but users commonly use slot numbers much greater than that. The AoE shelf and slot address space is often used sparsely. Instead of using a static mapping between AoE addresses and the block device minor number, the block device minor numbers are now allocated on demand. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: update copyright year in touched filesEd Cashin
Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: update internal version number to 49Ed Cashin
The internal version number of the aoe driver appears in a console message when the driver loads and is usually obtained by the user with the userland aoe-version tool, part of the aoetools.[1] Although this patchset includes bugfixes backported from higher-numbered versions published on the coraid.com website, it is a form of version 49. 1. http://aoetools.sourceforge.net/ Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: remove unused code and add cosmetic improvementsEd Cashin
This change removes some unused code and attempts to increase code consistency. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: increase net_device reference count while using itEd Cashin
This change eliminates the danger that the user could rmmod the driver for a network interface that is being used for AoE by the aoe driver. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: associate frames with the AoE storage targetEd Cashin
In the driver code, "target" and aoetgt refer to a particular remote interface on the AoE storage target. The latter is identified by its AoE major and minor addresses. Commands that are being sent to an AoE storage target {major, minor} can be sent or retransmitted to any of the remote MAC addresses associated with the AoE storage target. That is, frames are naturally associated with not an aoetgt (AoE major, AoE minor, remote MAC address) but an aoedev (AoE major, AoE minor). Making the code reflect that reality simplifies the driver, especially when the path to a remote MAC address becomes unusable. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: disallow unsupported AoE minor addressesEd Cashin
A guard is inserted to prevent AoE minor addresses (slot addresses) higher than 15 to be used, as they are not yet supported by the driver. There is a change coming that will allow the aoe driver to overcome this limit by using system device minor numbers dynamically, but until then, this guard prevents unexpected targets from being used by the driver when AoE targets with high minor numbers are on the AoE network. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: do revalidation steps in orderEd Cashin
The discovery process begins with an optional AoE config query command and an AoE config query response. Normally when an aoe device is already open, the config query response does not trigger an ATA identify device command to be sent out, since the response contains storage capacity information that, if changed, could surprise the user of the device. The userland "aoe-revalidate" tool uses a character device to trigger an AoE config query for a particular AoE storage target and an ATA device identify command, even when the device is open. This change causes the config query to go out first, reflecting the normal discovery sequence. The responses could come back in any order, so this change is fairly cosmetic. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: failover remote interface based on aoe_deadsecs parameterEd Cashin
The aoe_deadsecs module parameter allows the user to specify a hard limit on the number of seconds an AoE command can be retransmitted before the AoE block device is considered to have failed. Using aoe_deadsecs to determine the time we try using a different remote interface helps to ensure that the hard limit is not reached before we've tried to recover by sending to a different remote port. As a data storage target, the AoE target is unambiguously identified by its {major, minor} AoE address tuple, and an AoE target can have multiple MAC addresses. However, note that "target" in the driver code and comments means a {major, minor, MAC address} tuple, as in "somewhere to send packets". Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: use packets that work with the smallest-MTU local interfaceEd Cashin
Users with several network interfaces dedicated to AoE generally do not configure them to support different-sized AoE data payloads on purpose. For a given AoE target, there will be a set of local network interfaces that can reach it. Using only the payload that will fit in the smallest-sized MTU of all those local interfaces greatly simplifies the driver, especially in failure scenarios. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: use a kernel thread for transmissionsEd Cashin
The dev_queue_xmit function needs to have interrupts enabled, so the most simple way to get the locking right but still fulfill that requirement is to use a process that can call dev_queue_xmit serially over queued transmissions. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05aoe: become I/O request queue handler for increased user controlEd Cashin
To allow users to choose an elevator algorithm for their particular workloads, change from a make_request-style driver to an I/O-request-queue-handler-style driver. We have to do a couple of things that might be surprising. We manipulate the page _count directly on the assumption that we still have no guarantee that users of the block layer are prohibited from submitting bios containing pages with zero reference counts.[1] If such a prohibition now exists, I can get rid of the _count manipulation. Just as before this patch, we still keep track of the sk_buffs that the network layer still hasn't finished yet and cap the resources we use with a "pool" of skbs.[2] Now that the block layer maintains the disk stats, the aoe driver's diskstats function can go away. 1. https://lkml.org/lkml/2007/3/1/374 2. https://lkml.org/lkml/2007/7/6/241 Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>