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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-28 04:58:09 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-28 04:58:09 (GMT) |
commit | 2a7d2b96d5cba7568139d9ab157a0e97ab32440f (patch) | |
tree | ad029d8cc7b7068b7250e914360ec6315fdfa114 /lib/kfifo.c | |
parent | e3c4877de8b9d93bd47b6ee88eb594b1c1e10da5 (diff) | |
parent | b67bfe0d42cac56c512dd5da4b1b347a23f4b70a (diff) | |
download | linux-2a7d2b96d5cba7568139d9ab157a0e97ab32440f.tar.xz |
Merge branch 'akpm' (final batch from Andrew)
Merge third patch-bumb from Andrew Morton:
"This wraps me up for -rc1.
- Lots of misc stuff and things which were deferred/missed from
patchbombings 1 & 2.
- ocfs2 things
- lib/scatterlist
- hfsplus
- fatfs
- documentation
- signals
- procfs
- lockdep
- coredump
- seqfile core
- kexec
- Tejun's large IDR tree reworkings
- ipmi
- partitions
- nbd
- random() things
- kfifo
- tools/testing/selftests updates
- Sasha's large and pointless hlist cleanup"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (163 commits)
hlist: drop the node parameter from iterators
kcmp: make it depend on CHECKPOINT_RESTORE
selftests: add a simple doc
tools/testing/selftests/Makefile: rearrange targets
selftests/efivarfs: add create-read test
selftests/efivarfs: add empty file creation test
selftests: add tests for efivarfs
kfifo: fix kfifo_alloc() and kfifo_init()
kfifo: move kfifo.c from kernel/ to lib/
arch Kconfig: centralise CONFIG_ARCH_NO_VIRT_TO_BUS
w1: add support for DS2413 Dual Channel Addressable Switch
memstick: move the dereference below the NULL test
drivers/pps/clients/pps-gpio.c: use devm_kzalloc
Documentation/DMA-API-HOWTO.txt: fix typo
include/linux/eventfd.h: fix incorrect filename is a comment
mtd: mtd_stresstest: use prandom_bytes()
mtd: mtd_subpagetest: convert to use prandom library
mtd: mtd_speedtest: use prandom_bytes
mtd: mtd_pagetest: convert to use prandom library
mtd: mtd_oobtest: convert to use prandom library
...
Diffstat (limited to 'lib/kfifo.c')
-rw-r--r-- | lib/kfifo.c | 607 |
1 files changed, 607 insertions, 0 deletions
diff --git a/lib/kfifo.c b/lib/kfifo.c new file mode 100644 index 0000000..7b7f830 --- /dev/null +++ b/lib/kfifo.c @@ -0,0 +1,607 @@ +/* + * A generic kernel FIFO implementation + * + * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/log2.h> +#include <linux/uaccess.h> +#include <linux/kfifo.h> + +/* + * internal helper to calculate the unused elements in a fifo + */ +static inline unsigned int kfifo_unused(struct __kfifo *fifo) +{ + return (fifo->mask + 1) - (fifo->in - fifo->out); +} + +int __kfifo_alloc(struct __kfifo *fifo, unsigned int size, + size_t esize, gfp_t gfp_mask) +{ + /* + * round down to the next power of 2, since our 'let the indices + * wrap' technique works only in this case. + */ + size = roundup_pow_of_two(size); + + fifo->in = 0; + fifo->out = 0; + fifo->esize = esize; + + if (size < 2) { + fifo->data = NULL; + fifo->mask = 0; + return -EINVAL; + } + + fifo->data = kmalloc(size * esize, gfp_mask); + + if (!fifo->data) { + fifo->mask = 0; + return -ENOMEM; + } + fifo->mask = size - 1; + + return 0; +} +EXPORT_SYMBOL(__kfifo_alloc); + +void __kfifo_free(struct __kfifo *fifo) +{ + kfree(fifo->data); + fifo->in = 0; + fifo->out = 0; + fifo->esize = 0; + fifo->data = NULL; + fifo->mask = 0; +} +EXPORT_SYMBOL(__kfifo_free); + +int __kfifo_init(struct __kfifo *fifo, void *buffer, + unsigned int size, size_t esize) +{ + size /= esize; + + size = roundup_pow_of_two(size); + + fifo->in = 0; + fifo->out = 0; + fifo->esize = esize; + fifo->data = buffer; + + if (size < 2) { + fifo->mask = 0; + return -EINVAL; + } + fifo->mask = size - 1; + + return 0; +} +EXPORT_SYMBOL(__kfifo_init); + +static void kfifo_copy_in(struct __kfifo *fifo, const void *src, + unsigned int len, unsigned int off) +{ + unsigned int size = fifo->mask + 1; + unsigned int esize = fifo->esize; + unsigned int l; + + off &= fifo->mask; + if (esize != 1) { + off *= esize; + size *= esize; + len *= esize; + } + l = min(len, size - off); + + memcpy(fifo->data + off, src, l); + memcpy(fifo->data, src + l, len - l); + /* + * make sure that the data in the fifo is up to date before + * incrementing the fifo->in index counter + */ + smp_wmb(); +} + +unsigned int __kfifo_in(struct __kfifo *fifo, + const void *buf, unsigned int len) +{ + unsigned int l; + + l = kfifo_unused(fifo); + if (len > l) + len = l; + + kfifo_copy_in(fifo, buf, len, fifo->in); + fifo->in += len; + return len; +} +EXPORT_SYMBOL(__kfifo_in); + +static void kfifo_copy_out(struct __kfifo *fifo, void *dst, + unsigned int len, unsigned int off) +{ + unsigned int size = fifo->mask + 1; + unsigned int esize = fifo->esize; + unsigned int l; + + off &= fifo->mask; + if (esize != 1) { + off *= esize; + size *= esize; + len *= esize; + } + l = min(len, size - off); + + memcpy(dst, fifo->data + off, l); + memcpy(dst + l, fifo->data, len - l); + /* + * make sure that the data is copied before + * incrementing the fifo->out index counter + */ + smp_wmb(); +} + +unsigned int __kfifo_out_peek(struct __kfifo *fifo, + void *buf, unsigned int len) +{ + unsigned int l; + + l = fifo->in - fifo->out; + if (len > l) + len = l; + + kfifo_copy_out(fifo, buf, len, fifo->out); + return len; +} +EXPORT_SYMBOL(__kfifo_out_peek); + +unsigned int __kfifo_out(struct __kfifo *fifo, + void *buf, unsigned int len) +{ + len = __kfifo_out_peek(fifo, buf, len); + fifo->out += len; + return len; +} +EXPORT_SYMBOL(__kfifo_out); + +static unsigned long kfifo_copy_from_user(struct __kfifo *fifo, + const void __user *from, unsigned int len, unsigned int off, + unsigned int *copied) +{ + unsigned int size = fifo->mask + 1; + unsigned int esize = fifo->esize; + unsigned int l; + unsigned long ret; + + off &= fifo->mask; + if (esize != 1) { + off *= esize; + size *= esize; + len *= esize; + } + l = min(len, size - off); + + ret = copy_from_user(fifo->data + off, from, l); + if (unlikely(ret)) + ret = DIV_ROUND_UP(ret + len - l, esize); + else { + ret = copy_from_user(fifo->data, from + l, len - l); + if (unlikely(ret)) + ret = DIV_ROUND_UP(ret, esize); + } + /* + * make sure that the data in the fifo is up to date before + * incrementing the fifo->in index counter + */ + smp_wmb(); + *copied = len - ret; + /* return the number of elements which are not copied */ + return ret; +} + +int __kfifo_from_user(struct __kfifo *fifo, const void __user *from, + unsigned long len, unsigned int *copied) +{ + unsigned int l; + unsigned long ret; + unsigned int esize = fifo->esize; + int err; + + if (esize != 1) + len /= esize; + + l = kfifo_unused(fifo); + if (len > l) + len = l; + + ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied); + if (unlikely(ret)) { + len -= ret; + err = -EFAULT; + } else + err = 0; + fifo->in += len; + return err; +} +EXPORT_SYMBOL(__kfifo_from_user); + +static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to, + unsigned int len, unsigned int off, unsigned int *copied) +{ + unsigned int l; + unsigned long ret; + unsigned int size = fifo->mask + 1; + unsigned int esize = fifo->esize; + + off &= fifo->mask; + if (esize != 1) { + off *= esize; + size *= esize; + len *= esize; + } + l = min(len, size - off); + + ret = copy_to_user(to, fifo->data + off, l); + if (unlikely(ret)) + ret = DIV_ROUND_UP(ret + len - l, esize); + else { + ret = copy_to_user(to + l, fifo->data, len - l); + if (unlikely(ret)) + ret = DIV_ROUND_UP(ret, esize); + } + /* + * make sure that the data is copied before + * incrementing the fifo->out index counter + */ + smp_wmb(); + *copied = len - ret; + /* return the number of elements which are not copied */ + return ret; +} + +int __kfifo_to_user(struct __kfifo *fifo, void __user *to, + unsigned long len, unsigned int *copied) +{ + unsigned int l; + unsigned long ret; + unsigned int esize = fifo->esize; + int err; + + if (esize != 1) + len /= esize; + + l = fifo->in - fifo->out; + if (len > l) + len = l; + ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied); + if (unlikely(ret)) { + len -= ret; + err = -EFAULT; + } else + err = 0; + fifo->out += len; + return err; +} +EXPORT_SYMBOL(__kfifo_to_user); + +static int setup_sgl_buf(struct scatterlist *sgl, void *buf, + int nents, unsigned int len) +{ + int n; + unsigned int l; + unsigned int off; + struct page *page; + + if (!nents) + return 0; + + if (!len) + return 0; + + n = 0; + page = virt_to_page(buf); + off = offset_in_page(buf); + l = 0; + + while (len >= l + PAGE_SIZE - off) { + struct page *npage; + + l += PAGE_SIZE; + buf += PAGE_SIZE; + npage = virt_to_page(buf); + if (page_to_phys(page) != page_to_phys(npage) - l) { + sg_set_page(sgl, page, l - off, off); + sgl = sg_next(sgl); + if (++n == nents || sgl == NULL) + return n; + page = npage; + len -= l - off; + l = off = 0; + } + } + sg_set_page(sgl, page, len, off); + return n + 1; +} + +static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl, + int nents, unsigned int len, unsigned int off) +{ + unsigned int size = fifo->mask + 1; + unsigned int esize = fifo->esize; + unsigned int l; + unsigned int n; + + off &= fifo->mask; + if (esize != 1) { + off *= esize; + size *= esize; + len *= esize; + } + l = min(len, size - off); + + n = setup_sgl_buf(sgl, fifo->data + off, nents, l); + n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l); + + return n; +} + +unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo, + struct scatterlist *sgl, int nents, unsigned int len) +{ + unsigned int l; + + l = kfifo_unused(fifo); + if (len > l) + len = l; + + return setup_sgl(fifo, sgl, nents, len, fifo->in); +} +EXPORT_SYMBOL(__kfifo_dma_in_prepare); + +unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo, + struct scatterlist *sgl, int nents, unsigned int len) +{ + unsigned int l; + + l = fifo->in - fifo->out; + if (len > l) + len = l; + + return setup_sgl(fifo, sgl, nents, len, fifo->out); +} +EXPORT_SYMBOL(__kfifo_dma_out_prepare); + +unsigned int __kfifo_max_r(unsigned int len, size_t recsize) +{ + unsigned int max = (1 << (recsize << 3)) - 1; + + if (len > max) + return max; + return len; +} +EXPORT_SYMBOL(__kfifo_max_r); + +#define __KFIFO_PEEK(data, out, mask) \ + ((data)[(out) & (mask)]) +/* + * __kfifo_peek_n internal helper function for determinate the length of + * the next record in the fifo + */ +static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize) +{ + unsigned int l; + unsigned int mask = fifo->mask; + unsigned char *data = fifo->data; + + l = __KFIFO_PEEK(data, fifo->out, mask); + + if (--recsize) + l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8; + + return l; +} + +#define __KFIFO_POKE(data, in, mask, val) \ + ( \ + (data)[(in) & (mask)] = (unsigned char)(val) \ + ) + +/* + * __kfifo_poke_n internal helper function for storeing the length of + * the record into the fifo + */ +static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize) +{ + unsigned int mask = fifo->mask; + unsigned char *data = fifo->data; + + __KFIFO_POKE(data, fifo->in, mask, n); + + if (recsize > 1) + __KFIFO_POKE(data, fifo->in + 1, mask, n >> 8); +} + +unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize) +{ + return __kfifo_peek_n(fifo, recsize); +} +EXPORT_SYMBOL(__kfifo_len_r); + +unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf, + unsigned int len, size_t recsize) +{ + if (len + recsize > kfifo_unused(fifo)) + return 0; + + __kfifo_poke_n(fifo, len, recsize); + + kfifo_copy_in(fifo, buf, len, fifo->in + recsize); + fifo->in += len + recsize; + return len; +} +EXPORT_SYMBOL(__kfifo_in_r); + +static unsigned int kfifo_out_copy_r(struct __kfifo *fifo, + void *buf, unsigned int len, size_t recsize, unsigned int *n) +{ + *n = __kfifo_peek_n(fifo, recsize); + + if (len > *n) + len = *n; + + kfifo_copy_out(fifo, buf, len, fifo->out + recsize); + return len; +} + +unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf, + unsigned int len, size_t recsize) +{ + unsigned int n; + + if (fifo->in == fifo->out) + return 0; + + return kfifo_out_copy_r(fifo, buf, len, recsize, &n); +} +EXPORT_SYMBOL(__kfifo_out_peek_r); + +unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf, + unsigned int len, size_t recsize) +{ + unsigned int n; + + if (fifo->in == fifo->out) + return 0; + + len = kfifo_out_copy_r(fifo, buf, len, recsize, &n); + fifo->out += n + recsize; + return len; +} +EXPORT_SYMBOL(__kfifo_out_r); + +void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize) +{ + unsigned int n; + + n = __kfifo_peek_n(fifo, recsize); + fifo->out += n + recsize; +} +EXPORT_SYMBOL(__kfifo_skip_r); + +int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from, + unsigned long len, unsigned int *copied, size_t recsize) +{ + unsigned long ret; + + len = __kfifo_max_r(len, recsize); + + if (len + recsize > kfifo_unused(fifo)) { + *copied = 0; + return 0; + } + + __kfifo_poke_n(fifo, len, recsize); + + ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied); + if (unlikely(ret)) { + *copied = 0; + return -EFAULT; + } + fifo->in += len + recsize; + return 0; +} +EXPORT_SYMBOL(__kfifo_from_user_r); + +int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to, + unsigned long len, unsigned int *copied, size_t recsize) +{ + unsigned long ret; + unsigned int n; + + if (fifo->in == fifo->out) { + *copied = 0; + return 0; + } + + n = __kfifo_peek_n(fifo, recsize); + if (len > n) + len = n; + + ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied); + if (unlikely(ret)) { + *copied = 0; + return -EFAULT; + } + fifo->out += n + recsize; + return 0; +} +EXPORT_SYMBOL(__kfifo_to_user_r); + +unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo, + struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) +{ + if (!nents) + BUG(); + + len = __kfifo_max_r(len, recsize); + + if (len + recsize > kfifo_unused(fifo)) + return 0; + + return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize); +} +EXPORT_SYMBOL(__kfifo_dma_in_prepare_r); + +void __kfifo_dma_in_finish_r(struct __kfifo *fifo, + unsigned int len, size_t recsize) +{ + len = __kfifo_max_r(len, recsize); + __kfifo_poke_n(fifo, len, recsize); + fifo->in += len + recsize; +} +EXPORT_SYMBOL(__kfifo_dma_in_finish_r); + +unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo, + struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) +{ + if (!nents) + BUG(); + + len = __kfifo_max_r(len, recsize); + + if (len + recsize > fifo->in - fifo->out) + return 0; + + return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize); +} +EXPORT_SYMBOL(__kfifo_dma_out_prepare_r); + +void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize) +{ + unsigned int len; + + len = __kfifo_peek_n(fifo, recsize); + fifo->out += len + recsize; +} +EXPORT_SYMBOL(__kfifo_dma_out_finish_r); |