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| author | Ming Lei <ming.lei@redhat.com> | 2019-06-18 09:37:55 +0800 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2019-06-20 15:21:33 -0400 |
| commit | 57ef4e510939e305ad905cc54b8031401ff5450e (patch) | |
| tree | 3238204aac5cace7ffda1f7eb2d1b4dce8b49152 | |
| parent | 1b3a4640106603ce6b3ad261ef4d20ea60e9790b (diff) | |
| download | lwn-57ef4e510939e305ad905cc54b8031401ff5450e.tar.gz lwn-57ef4e510939e305ad905cc54b8031401ff5450e.zip | |
scsi: ppa: use sg helper to iterate over scatterlist
Unlike the legacy I/O path, scsi-mq preallocates a large array to hold
the scatterlist for each request. This static allocation can consume
substantial amounts of memory on modern controllers which support a
large number of concurrently outstanding requests.
To facilitate a switch to a smaller static allocation combined with a
dynamic allocation for requests that need it, we need to make sure all
SCSI drivers handle chained scatterlists correctly.
Convert remaining drivers that directly dereference the scatterlist
array to using the iterator functions.
[mkp: clarified commit message]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/scsi/ppa.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/scsi/ppa.c b/drivers/scsi/ppa.c index 35213082e933..a406cc825426 100644 --- a/drivers/scsi/ppa.c +++ b/drivers/scsi/ppa.c @@ -590,7 +590,7 @@ static int ppa_completion(struct scsi_cmnd *cmd) if (cmd->SCp.buffer && !cmd->SCp.this_residual) { /* if scatter/gather, advance to the next segment */ if (cmd->SCp.buffers_residual--) { - cmd->SCp.buffer++; + cmd->SCp.buffer = sg_next(cmd->SCp.buffer); cmd->SCp.this_residual = cmd->SCp.buffer->length; cmd->SCp.ptr = sg_virt(cmd->SCp.buffer); |