Attachment 660930 Details for Bug 883429 – mmap-cache.patch

[patch] mmap-cache.patch

mmap-cache.patch (text/plain), 1.53 KB, created by Florian Weimer on 2012-12-10 15:57:18 UTC

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Creator: Florian Weimer

Created: 2012-12-10 15:57:18 UTC

Size: 1.53 KB

patch

obsolete

>diff --git a/src/sss_client/nss_mc_common.c b/src/sss_client/nss_mc_common.c
>index a361f57..5c36e7b 100644
>--- a/src/sss_client/nss_mc_common.c
>+++ b/src/sss_client/nss_mc_common.c
>@@ -45,13 +45,15 @@ errno_t sss_nss_check_header(struct sss_cli_mc_ctx *ctx)
> 
>     /* retry barrier protected reading max 5 times then give up */
>     for (count = 5; count > 0; count--) {
>-        memcpy(&h, ctx->mmap_base, sizeof(struct sss_mc_header));
>-        /* we need a barrier here to make sure the compiler does not optimize
>-         * too much and avoids updating the register for the next check */
>-        __sync_synchronize();
>-        if (MC_VALID_BARRIER(h.b1) && h.b1 == h.b2) {
>-            /* record is consistent so we can proceed */
>-            break;
>+        struct sss_mc_header *ph = ctx->mmap_base;
>+        uint32_t b1 = ph->b1;
>+        if (MC_VALID_BARRIER(b1)) {
>+            __sync_synchronize();
>+            memcpy(&h, ph, sizeof(struct sss_mc_header));
>+            __sync_synchronize();
>+            if (ph->b2 == b1) {
>+                break;
>+            }
>         }
>     }
>     if (count == 0) {
>@@ -219,9 +221,8 @@ errno_t sss_nss_mc_get_record(struct sss_cli_mc_ctx *ctx,
>         rec = (struct sss_mc_rec *)rec_buf;
> 
>         /* we must check data is consistent again after the copy */
>-        if (MC_VALID_BARRIER(rec->b1) &&
>-            rec->b1 == rec->b2 &&
>-            rec->len == rec_len) {
>+        __sync_synchronize();
>+        if (rec->b2 == b1) {
>             /* record is consistent, use it */
>             break;
>         }

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Attachments on bug 883429: 660930 | 661730 | 662504