From: Ming Lei Date: Tue, 18 Jun 2019 01:37:56 +0000 (+0800) Subject: scsi: wd33c93: use sg helper to iterate over scatterlist X-Git-Tag: v5.3-rc1~130^2~7 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c3c0fd9b108f6360ceaade790571be097df1f3ef;p=thirdparty%2Fkernel%2Flinux.git scsi: wd33c93: 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 Reviewed-by: Bart Van Assche Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/wd33c93.c b/drivers/scsi/wd33c93.c index 74be04f2357c0..ae5935c0a1497 100644 --- a/drivers/scsi/wd33c93.c +++ b/drivers/scsi/wd33c93.c @@ -744,7 +744,7 @@ transfer_bytes(const wd33c93_regs regs, struct scsi_cmnd *cmd, * source or destination for THIS transfer. */ if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) { - ++cmd->SCp.buffer; + cmd->SCp.buffer = sg_next(cmd->SCp.buffer); --cmd->SCp.buffers_residual; cmd->SCp.this_residual = cmd->SCp.buffer->length; cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);