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authorFinn Thain <fthain@telegraphics.com.au>2019-06-18 04:37:52 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2019-06-20 22:21:33 +0300
commita7a253ba6c26490fb132ee682661c03a6c454fd5 (patch)
treeeebf3a0d11bfc6c7ada97c9a6ea88fcf3ed85baf /drivers/scsi/aha152x.c
parent013be03840c2ba3a2717f9cee457f01fdc4d8436 (diff)
downloadlinux-a7a253ba6c26490fb132ee682661c03a6c454fd5.tar.xz
scsi: aha152x: 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. Finn added the change to replace SCp.buffers_residual with sg_is_last() for fixing updating it, and the similar change has been applied on NCR5380.c [mkp: clarified commit message] Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/aha152x.c')
-rw-r--r--drivers/scsi/aha152x.c46
1 files changed, 23 insertions, 23 deletions
diff --git a/drivers/scsi/aha152x.c b/drivers/scsi/aha152x.c
index 97872838b983..f07f3fa9b58d 100644
--- a/drivers/scsi/aha152x.c
+++ b/drivers/scsi/aha152x.c
@@ -948,7 +948,6 @@ static int aha152x_internal_queue(struct scsi_cmnd *SCpnt,
SCp.ptr : buffer pointer
SCp.this_residual : buffer length
SCp.buffer : next buffer
- SCp.buffers_residual : left buffers in list
SCp.phase : current state of the command */
if ((phase & resetting) || !scsi_sglist(SCpnt)) {
@@ -956,13 +955,11 @@ static int aha152x_internal_queue(struct scsi_cmnd *SCpnt,
SCpnt->SCp.this_residual = 0;
scsi_set_resid(SCpnt, 0);
SCpnt->SCp.buffer = NULL;
- SCpnt->SCp.buffers_residual = 0;
} else {
scsi_set_resid(SCpnt, scsi_bufflen(SCpnt));
SCpnt->SCp.buffer = scsi_sglist(SCpnt);
SCpnt->SCp.ptr = SG_ADDRESS(SCpnt->SCp.buffer);
SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
- SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
}
DO_LOCK(flags);
@@ -2030,10 +2027,9 @@ static void datai_run(struct Scsi_Host *shpnt)
}
if (CURRENT_SC->SCp.this_residual == 0 &&
- CURRENT_SC->SCp.buffers_residual > 0) {
+ !sg_is_last(CURRENT_SC->SCp.buffer)) {
/* advance to next buffer */
- CURRENT_SC->SCp.buffers_residual--;
- CURRENT_SC->SCp.buffer++;
+ CURRENT_SC->SCp.buffer = sg_next(CURRENT_SC->SCp.buffer);
CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer);
CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length;
}
@@ -2136,10 +2132,10 @@ static void datao_run(struct Scsi_Host *shpnt)
CMD_INC_RESID(CURRENT_SC, -2 * data_count);
}
- if(CURRENT_SC->SCp.this_residual==0 && CURRENT_SC->SCp.buffers_residual>0) {
+ if (CURRENT_SC->SCp.this_residual == 0 &&
+ !sg_is_last(CURRENT_SC->SCp.buffer)) {
/* advance to next buffer */
- CURRENT_SC->SCp.buffers_residual--;
- CURRENT_SC->SCp.buffer++;
+ CURRENT_SC->SCp.buffer = sg_next(CURRENT_SC->SCp.buffer);
CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer);
CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length;
}
@@ -2158,22 +2154,26 @@ static void datao_run(struct Scsi_Host *shpnt)
static void datao_end(struct Scsi_Host *shpnt)
{
if(TESTLO(DMASTAT, DFIFOEMP)) {
- int data_count = (DATA_LEN - scsi_get_resid(CURRENT_SC)) -
- GETSTCNT();
+ u32 datao_cnt = GETSTCNT();
+ int datao_out = DATA_LEN - scsi_get_resid(CURRENT_SC);
+ int done;
+ struct scatterlist *sg = scsi_sglist(CURRENT_SC);
- CMD_INC_RESID(CURRENT_SC, data_count);
+ CMD_INC_RESID(CURRENT_SC, datao_out - datao_cnt);
- data_count -= CURRENT_SC->SCp.ptr -
- SG_ADDRESS(CURRENT_SC->SCp.buffer);
- while(data_count>0) {
- CURRENT_SC->SCp.buffer--;
- CURRENT_SC->SCp.buffers_residual++;
- data_count -= CURRENT_SC->SCp.buffer->length;
+ done = scsi_bufflen(CURRENT_SC) - scsi_get_resid(CURRENT_SC);
+ /* Locate the first SG entry not yet sent */
+ while (done > 0 && !sg_is_last(sg)) {
+ if (done < sg->length)
+ break;
+ done -= sg->length;
+ sg = sg_next(sg);
}
- CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer) -
- data_count;
- CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length +
- data_count;
+
+ CURRENT_SC->SCp.buffer = sg;
+ CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer) + done;
+ CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length -
+ done;
}
SETPORT(SXFRCTL0, CH1|CLRCH1|CLRSTCNT);
@@ -2501,7 +2501,7 @@ static void get_command(struct seq_file *m, struct scsi_cmnd * ptr)
seq_printf(m, "); resid=%d; residual=%d; buffers=%d; phase |",
scsi_get_resid(ptr), ptr->SCp.this_residual,
- ptr->SCp.buffers_residual);
+ sg_nents(ptr->SCp.buffer) - 1);
if (ptr->SCp.phase & not_issued)
seq_puts(m, "not issued|");