1 files changed, 17 insertions, 18 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 74dcf19cfe68..758b77296404 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -547,7 +547,7 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                                 rw = WRITE_FUA;
                         else
                                 rw = WRITE;
-                        if (test_and_clear_bit(R5_Discard, &sh->dev[i].flags))
+                        if (test_bit(R5_Discard, &sh->dev[i].flags))
                                 rw |= REQ_DISCARD;
                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
                         rw = READ;
@@ -1172,11 +1172,9 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
                                         set_bit(R5_WantFUA, &dev->flags);
                                 if (wbi->bi_rw & REQ_SYNC)
                                         set_bit(R5_SyncIO, &dev->flags);
-                                if (wbi->bi_rw & REQ_DISCARD) {
-                                        memset(page_address(dev->page), 0,
-                                                STRIPE_SECTORS << 9);
+                                if (wbi->bi_rw & REQ_DISCARD)
                                         set_bit(R5_Discard, &dev->flags);
-                                } else
+                                else
                                         tx = async_copy_data(1, wbi, dev->page,
                                                 dev->sector, tx);
                                 wbi = r5_next_bio(wbi, dev->sector);
@@ -1194,7 +1192,7 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
         int pd_idx = sh->pd_idx;
         int qd_idx = sh->qd_idx;
         int i;
-        bool fua = false, sync = false;
+        bool fua = false, sync = false, discard = false;
 
         pr_debug("%s: stripe %llu\n", __func__,
                 (unsigned long long)sh->sector);
@@ -1202,13 +1200,15 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
         for (i = disks; i--; ) {
                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
+                discard |= test_bit(R5_Discard, &sh->dev[i].flags);
         }
 
         for (i = disks; i--; ) {
                 struct r5dev *dev = &sh->dev[i];
 
                 if (dev->written || i == pd_idx || i == qd_idx) {
-                        set_bit(R5_UPTODATE, &dev->flags);
+                        if (!discard)
+                                set_bit(R5_UPTODATE, &dev->flags);
                         if (fua)
                                 set_bit(R5_WantFUA, &dev->flags);
                         if (sync)
@@ -1252,8 +1252,6 @@ ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
         }
         if (i >= sh->disks) {
                 atomic_inc(&sh->count);
-                memset(page_address(sh->dev[pd_idx].page), 0,
-                        STRIPE_SECTORS << 9);
                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
                 ops_complete_reconstruct(sh);
                 return;
@@ -1314,10 +1312,6 @@ ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
         }
         if (i >= sh->disks) {
                 atomic_inc(&sh->count);
-                memset(page_address(sh->dev[sh->pd_idx].page), 0,
-                        STRIPE_SECTORS << 9);
-                memset(page_address(sh->dev[sh->qd_idx].page), 0,
-                        STRIPE_SECTORS << 9);
                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
                 ops_complete_reconstruct(sh);
@@ -2775,7 +2769,8 @@ static void handle_stripe_clean_event(struct r5conf *conf,
                 if (sh->dev[i].written) {
                         dev = &sh->dev[i];
                         if (!test_bit(R5_LOCKED, &dev->flags) &&
-                                test_bit(R5_UPTODATE, &dev->flags)) {
+                            (test_bit(R5_UPTODATE, &dev->flags) ||
+                             test_and_clear_bit(R5_Discard, &dev->flags))) {
                                 /* We can return any write requests */
                                 struct bio *wbi, *wbi2;
                                 pr_debug("Return write for disc %d\n", i);
@@ -3493,10 +3488,12 @@ static void handle_stripe(struct stripe_head *sh)
         if (s.written &&
             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
                              && !test_bit(R5_LOCKED, &pdev->flags)
-                             && test_bit(R5_UPTODATE, &pdev->flags)))) &&
+                             && (test_bit(R5_UPTODATE, &pdev->flags) ||
+                                 test_bit(R5_Discard, &pdev->flags))))) &&
             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
                              && !test_bit(R5_LOCKED, &qdev->flags)
-                             && test_bit(R5_UPTODATE, &qdev->flags)))))
+                             && (test_bit(R5_UPTODATE, &qdev->flags) ||
+                                 test_bit(R5_Discard, &qdev->flags))))))
                 handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
 
         /* Now we might consider reading some blocks, either to check/generate
@@ -3523,9 +3520,11 @@ static void handle_stripe(struct stripe_head *sh)
                 /* All the 'written' buffers and the parity block are ready to
                  * be written back to disk
                  */
-                BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
+                BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
+                       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
                 BUG_ON(sh->qd_idx >= 0 &&
-                       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags));
+                       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
+                       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
                 for (i = disks; i--; ) {
                         struct r5dev *dev = &sh->dev[i];
                         if (test_bit(R5_LOCKED, &dev->flags) &&