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scsi: mvumi: 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 and folded in build fix reported by zeroday]

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Ming Lei 2019-06-18 09:37:45 +08:00 committed by Martin K. Petersen
parent 46e8e475a1
commit 3c1a30df6d
1 changed files with 5 additions and 6 deletions
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11
drivers/scsi/mvumi.c
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@ -211,23 +211,22 @@ static int mvumi_make_sgl(struct mvumi_hba *mhba, struct scsi_cmnd *scmd,
unsigned int sgnum = scsi_sg_count(scmd);
dma_addr_t busaddr;
sg = scsi_sglist(scmd);
*sg_count = dma_map_sg(&mhba->pdev->dev, sg, sgnum,
*sg_count = dma_map_sg(&mhba->pdev->dev, scsi_sglist(scmd), sgnum,
scmd->sc_data_direction);
if (*sg_count > mhba->max_sge) {
dev_err(&mhba->pdev->dev,
"sg count[0x%x] is bigger than max sg[0x%x].\n",
*sg_count, mhba->max_sge);
dma_unmap_sg(&mhba->pdev->dev, sg, sgnum,
dma_unmap_sg(&mhba->pdev->dev, scsi_sglist(scmd), sgnum,
scmd->sc_data_direction);
return -1;
}
for (i = 0; i < *sg_count; i++) {
busaddr = sg_dma_address(&sg[i]);
scsi_for_each_sg(scmd, sg, *sg_count, i) {
busaddr = sg_dma_address(sg);
m_sg->baseaddr_l = cpu_to_le32(lower_32_bits(busaddr));
m_sg->baseaddr_h = cpu_to_le32(upper_32_bits(busaddr));
m_sg->flags = 0;
sgd_setsz(mhba, m_sg, cpu_to_le32(sg_dma_len(&sg[i])));
sgd_setsz(mhba, m_sg, cpu_to_le32(sg_dma_len(sg)));
if ((i + 1) == *sg_count)
m_sg->flags |= 1U << mhba->eot_flag;