dmaengine: idxd: fix retry value to be constant for duration of function call

mainline inclusion
from mainline-v5.18
commit bc3452cd
category: bugfix
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I596WO
CVE: NA

Intel-SIG: commit bc3452cd dmaengine: idxd: fix retry value to be constant for duration of function call.
Incremental backporting patches for DSA/IAA on Intel Xeon platform.

--------------------------------

When retries is compared to wq->enqcmds_retries each loop of idxd_enqcmds(),
wq->enqcmds_retries can potentially changed by user. Assign the value
of retries to wq->enqcmds_retries during initialization so it is the
original value set when entering the function.

Fixes: 7930d855 ("dmaengine: idxd: add knob for enqcmds retries")
Suggested-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/165031760154.3658664.1983547716619266558.stgit@djiang5-desk3.ch.intel.comSigned-off-by: NVinod Koul <vkoul@kernel.org>
Signed-off-by: NXiaochen Shen <xiaochen.shen@intel.com>

drivers/dma/idxd/submit.c

@@ -150,7 +150,7 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
  */
 int idxd_enqcmds(struct idxd_wq *wq, void __iomem *portal, const void *desc)
 {
-	unsigned int retries = 0;
+	unsigned int retries = wq->enqcmds_retries;
 	int rc;
 
 	do {
@@ -158,7 +158,7 @@ int idxd_enqcmds(struct idxd_wq *wq, void __iomem *portal, const void *desc)
 		if (rc == 0)
 			break;
 		cpu_relax();
-	} while (retries++ < wq->enqcmds_retries);
+	} while (retries--);
 
 	return rc;
 }