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| author | Christoph Hellwig <hch@lst.de> | 2014-04-15 12:38:31 (GMT) |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-07-25 21:16:21 (GMT) |
| commit | c53c6d6a68b13b1dff2892551b56cfdc07887d9e (patch) | |
| tree | 8bd6ddc1ff0f33e357ad6c230f62fd7b1cf1b28a /drivers | |
| parent | f6d47e74fcb2814225e429c94355ad1c551daffb (diff) | |
| download | linux-c53c6d6a68b13b1dff2892551b56cfdc07887d9e.tar.xz | |
scatterlist: allow chaining to preallocated chunks
Blk-mq drivers usually preallocate their S/G list as part of the request,
but if we want to support the very large S/G lists currently supported by
the SCSI code that would tie up a lot of memory in the preallocated request
pool. Add support to the scatterlist code so that it can initialize a
S/G list that uses a preallocated first chunks and dynamically allocated
additional chunks. That way the scsi-mq code can preallocate a first
page worth of S/G entries as part of the request, and dynamically extend
the S/G list when needed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 8723abe..bbd7a0a 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -564,6 +564,11 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) return mempool_alloc(sgp->pool, gfp_mask); } +static void scsi_free_sgtable(struct scsi_data_buffer *sdb) +{ + __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, false, scsi_sg_free); +} + static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, gfp_t gfp_mask) { @@ -572,19 +577,12 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, BUG_ON(!nents); ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, - gfp_mask, scsi_sg_alloc); + NULL, gfp_mask, scsi_sg_alloc); if (unlikely(ret)) - __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, - scsi_sg_free); - + scsi_free_sgtable(sdb); return ret; } -static void scsi_free_sgtable(struct scsi_data_buffer *sdb) -{ - __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); -} - /* * Function: scsi_release_buffers() * |