[S390] cio: replace subchannel evaluation queue with bitmap

Use a bitmap for indicating which subchannels require evaluation
instead of allocating memory for each evaluation request. This
approach reduces memory consumption during recovery in case of
massive evaluation request occurrence and removes the need for
memory allocation failure handling.

Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 6 insertions, 18 deletions

diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c
index afd8a3c0f8d6..644a06eba828 100644
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -45,14 +45,13 @@ static int
 s390_collect_crw_info(void *param)
 {
         struct crw crw[2];
-        int ccode, ret, slow;
+        int ccode;
         struct semaphore *sem;
         unsigned int chain;
 
         sem = (struct semaphore *)param;
 repeat:
         down_interruptible(sem);
-        slow = 0;
         chain = 0;
         while (1) {
                 if (unlikely(chain > 1)) {
@@ -85,9 +84,8 @@ repeat:
                 /* Check for overflows. */
                 if (crw[chain].oflw) {
                         pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
-                        css_reiterate_subchannels();
+                        css_schedule_eval_all();
                         chain = 0;
-                        slow = 1;
                         continue;
                 }
                 switch (crw[chain].rsc) {
@@ -95,10 +93,7 @@ repeat:
                         if (crw[0].chn && !chain)
                                 break;
                         pr_debug("source is subchannel %04X\n", crw[0].rsid);
-                        ret = css_process_crw (crw[0].rsid,
-                                               chain ? crw[1].rsid : 0);
-                        if (ret == -EAGAIN)
-                                slow = 1;
+                        css_process_crw(crw[0].rsid, chain ? crw[1].rsid : 0);
                         break;
                 case CRW_RSC_MONITOR:
                         pr_debug("source is monitoring facility\n");
@@ -117,28 +112,23 @@ repeat:
                         }
                         switch (crw[0].erc) {
                         case CRW_ERC_IPARM: /* Path has come. */
-                                ret = chp_process_crw(crw[0].rsid, 1);
+                                chp_process_crw(crw[0].rsid, 1);
                                 break;
                         case CRW_ERC_PERRI: /* Path has gone. */
                         case CRW_ERC_PERRN:
-                                ret = chp_process_crw(crw[0].rsid, 0);
+                                chp_process_crw(crw[0].rsid, 0);
                                 break;
                         default:
                                 pr_debug("Don't know how to handle erc=%x\n",
                                          crw[0].erc);
-                                ret = 0;
                         }
-                        if (ret == -EAGAIN)
-                                slow = 1;
                         break;
                 case CRW_RSC_CONFIG:
                         pr_debug("source is configuration-alert facility\n");
                         break;
                 case CRW_RSC_CSS:
                         pr_debug("source is channel subsystem\n");
-                        ret = chsc_process_crw();
-                        if (ret == -EAGAIN)
-                                slow = 1;
+                        chsc_process_crw();
                         break;
                 default:
                         pr_debug("unknown source\n");
@@ -147,8 +137,6 @@ repeat:
                 /* chain is always 0 or 1 here. */
                 chain = crw[chain].chn ? chain + 1 : 0;
         }
-        if (slow)
-                queue_work(slow_path_wq, &slow_path_work);
         goto repeat;
         return 0;
 }