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Handling of max_sectors backend limit added

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git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@2173 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Vladislav Bolkhovitin
2010-09-22 19:24:15 +00:00
parent d0c79c47a6
commit 38327e08ae
1 changed files with 51 additions and 13 deletions
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64
scst/src/dev_handlers/scst_disk.c
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@@ -463,6 +463,14 @@ out:
return res;
}
static void disk_restore_sg(struct disk_work *work)
{
disk_cdb_set_transfer_data(work->cmd->cdb, work->save_lba, work->save_len);
work->cmd->sg = work->save_sg;
work->cmd->sg_cnt = work->save_sg_cnt;
return;
}
static void disk_cmd_done(void *data, char *sense, int result, int resid)
{
struct disk_work *work = data;
@@ -477,9 +485,7 @@ static void disk_cmd_done(void *data, char *sense, int result, int resid)
work->result = result;
disk_cdb_set_transfer_data(work->cmd->cdb, work->save_lba, work->save_len);
work->cmd->sg = work->save_sg;
work->cmd->sg_cnt = work->save_sg_cnt;
disk_restore_sg(work);
scst_pass_through_cmd_done(work->cmd, sense, result, resid + work->left);
@@ -496,20 +502,52 @@ static int disk_exec(struct scst_cmd *cmd)
int res, rc;
struct disk_params *params = (struct disk_params *)cmd->dev->dh_priv;
struct disk_work work;
unsigned int offset, cur_len;
unsigned int offset, cur_len; /* in blocks */
struct scatterlist *sg, *start_sg;
int cur_sg_cnt;
int sg_tablesize = cmd->dev->scsi_dev->host->sg_tablesize;
int max_sectors = cmd->dev->scsi_dev->host->max_sectors;
int num, j;
TRACE_ENTRY();
if (likely((cmd->sg_cnt <= sg_tablesize) &&
(cmd->out_sg_cnt <= sg_tablesize))) {
if (unlikely(((max_sectors << params->block_shift) & ~PAGE_MASK) != 0)) {
int mlen = max_sectors << params->block_shift;
int pg = ((mlen >> PAGE_SHIFT) + ((mlen & ~PAGE_MASK) != 0)) - 1;
int adj_len = pg << PAGE_SHIFT;
max_sectors = adj_len >> params->block_shift;
if (max_sectors == 0) {
PRINT_ERROR("Too low max sectors %d", max_sectors);
goto out_error;
}
}
if (unlikely((cmd->bufflen >> params->block_shift) > max_sectors)) {
if ((cmd->out_bufflen >> params->block_shift) > max_sectors) {
PRINT_ERROR("Too limited max_sectors %d for "
"bidirectional cmd %x (out_bufflen %d)",
max_sectors, cmd->cdb[0], cmd->out_bufflen);
/* Let lower level handle it */
res = SCST_EXEC_NOT_COMPLETED;
goto out;
}
goto split;
}
if (likely(cmd->sg_cnt <= sg_tablesize)) {
res = SCST_EXEC_NOT_COMPLETED;
goto out;
}
split:
sBUG_ON(cmd->out_sg_cnt > sg_tablesize);
sBUG_ON((cmd->out_bufflen >> params->block_shift) > max_sectors);
/*
* We don't support changing BIDI CDBs (see disk_on_sg_tablesize_low()),
* so use only sg_cnt
*/
memset(&work, 0, sizeof(work));
work.cmd = cmd;
work.save_sg = cmd->sg;
@@ -529,10 +567,10 @@ static int disk_exec(struct scst_cmd *cmd)
cmd->driver_status = 0;
TRACE_DBG("cmd %p, save_sg %p, save_sg_cnt %d, save_lba %lld, "
"save_len %d (sg_tablesize %d, sizeof(*sg) 0x%zx)", cmd,
work.save_sg, work.save_sg_cnt,
"save_len %d (sg_tablesize %d, max_sectors %d, block_shift %d, "
"sizeof(*sg) 0x%zx)", cmd, work.save_sg, work.save_sg_cnt,
(unsigned long long)work.save_lba, work.save_len,
sg_tablesize, sizeof(*sg));
sg_tablesize, max_sectors, params->block_shift, sizeof(*sg));
/*
* If we submit all chunks async'ly, it will be very not trivial what
@@ -566,7 +604,9 @@ static int disk_exec(struct scst_cmd *cmd)
"cur_sg_cnt %d, start_sg %p", l, j, num, offset,
cur_len, cur_sg_cnt, start_sg);
if (((num % sg_tablesize) == 0) || (num == work.save_sg_cnt)) {
if (((num % sg_tablesize) == 0) ||
(num == work.save_sg_cnt) ||
(cur_len >= max_sectors)) {
TRACE_DBG("%s", "Execing...");
disk_cdb_set_transfer_data(cmd->cdb,
@@ -607,9 +647,7 @@ static int disk_exec(struct scst_cmd *cmd)
cmd->completed = 1;
out_restore:
disk_cdb_set_transfer_data(cmd->cdb, work.save_lba, work.save_len);
cmd->sg = work.save_sg;
cmd->sg_cnt = work.save_sg_cnt;
disk_restore_sg(&work);
out_done:
res = SCST_EXEC_COMPLETED;