Cache bypass: Remove AFS_KMAP_ATOMIC

[openafs.git] / src / afs / afs_bypasscache.c

diff --git a/src/afs/afs_bypasscache.c b/src/afs/afs_bypasscache.c
index e23c559..8d7e601 100644 (file)
--- a/src/afs/afs_bypasscache.c
+++ b/src/afs/afs_bypasscache.c
@@ -79,7 +79,6 @@
 #define LockPage(pp) lock_page(pp)
 #define UnlockPage(pp) unlock_page(pp)
 #endif
-#define AFS_KMAP_ATOMIC
 
 #ifndef afs_min
 #define afs_min(A,B) ((A)<(B)) ? (A) : (B)
@@ -143,9 +142,6 @@ afs_TransitionToBypass(struct vcache *avc,
     if (!avc)
        return;
 
-    if (avc->f.states & FCSBypass)
-       osi_Panic("afs_TransitionToBypass: illegal transition to bypass--already FCSBypass\n");
-
     if (aflags & TRANSChangeDesiredBit)
        setDesire = 1;
     if (aflags & TRANSSetManualBit)
@@ -156,7 +152,14 @@ afs_TransitionToBypass(struct vcache *avc,
 #else
     AFS_GLOCK();
 #endif
+
     ObtainWriteLock(&avc->lock, 925);
+    /*
+     * Someone may have beat us to doing the transition - we had no lock
+     * when we checked the flag earlier.  No cause to panic, just return.
+     */
+    if (avc->f.states & FCSBypass)
+       goto done;
 
     /* If we never cached this, just change state */
     if (setDesire && (!(avc->cachingStates & FCSBypass))) {
@@ -220,9 +223,6 @@ afs_TransitionToCaching(struct vcache *avc,
     if (!avc)
        return;
 
-    if (!(avc->f.states & FCSBypass))
-       osi_Panic("afs_TransitionToCaching: illegal transition to caching--already caching\n");
-
     if (aflags & TRANSChangeDesiredBit)
        resetDesire = 1;
     if (aflags & TRANSSetManualBit)
@@ -234,6 +234,12 @@ afs_TransitionToCaching(struct vcache *avc,
     AFS_GLOCK();
 #endif
     ObtainWriteLock(&avc->lock, 926);
+    /*
+     * Someone may have beat us to doing the transition - we had no lock
+     * when we checked the flag earlier.  No cause to panic, just return.
+     */
+    if (!(avc->f.states & FCSBypass))
+       goto done;
 
     /* Ok, we actually do need to flush */
     ObtainWriteLock(&afs_xcbhash, 957);
@@ -255,6 +261,7 @@ afs_TransitionToCaching(struct vcache *avc,
        avc->cachingStates |= FCSManuallySet;
     avc->cachingTransitions++;
 
+done:
     ReleaseWriteLock(&avc->lock);
 #ifdef AFS_BOZONLOCK_ENV
     afs_BozonUnlock(&avc->pvnLock, avc);
@@ -277,18 +284,18 @@ afs_TransitionToCaching(struct vcache *avc,
        ciov = auio->uio_iov; \
        iovmax = auio->uio_iovcnt - 1;  \
        pp = (struct page*) ciov->iov_base;     \
-       afs_warn("BYPASS: Unlocking pages..."); \
        while(1) { \
-           if(pp != NULL && PageLocked(pp)) \
-               UnlockPage(pp); \
-            put_page(pp); /* decrement refcount */ \
+           if (pp) { \
+               if (PageLocked(pp)) \
+                   UnlockPage(pp);     \
+               put_page(pp); /* decrement refcount */ \
+           } \
            iovno++; \
            if(iovno > iovmax) \
                break; \
            ciov = (auio->uio_iov + iovno);     \
            pp = (struct page*) ciov->iov_base; \
        } \
-       afs_warn("Pages Unlocked.\n"); \
     } while(0)
 #else
 #ifdef UKERNEL
@@ -314,11 +321,7 @@ afs_NoCacheFetchProc(struct rx_call *acall,
     struct iovec *ciov;
     struct page *pp;
     char *address;
-#ifdef AFS_KMAP_ATOMIC
     char *page_buffer = osi_Alloc(PAGE_SIZE);
-#else
-    char *page_buffer = NULL;
-#endif
 
     ciov = auio->uio_iov;
     pp = (struct page*) ciov->iov_base;
@@ -347,6 +350,13 @@ afs_NoCacheFetchProc(struct rx_call *acall,
            goto done;
        }
 
+       /* If we get a 0 length reply, time to cleanup and return */
+       if (length == 0) {
+           unlock_and_release_pages(auio);
+           result = 0;
+           goto done;
+       }
+
        /*
         * The fetch protocol is extended for the AFS/DFS translator
         * to allow multiple blocks of data, each with its own length,
@@ -368,21 +378,7 @@ afs_NoCacheFetchProc(struct rx_call *acall,
            clen = ciov->iov_len - iovoff;
            tlen = afs_min(length, clen);
 #ifdef AFS_LINUX24_ENV
-#ifndef AFS_KMAP_ATOMIC
-           if(pp)
-               address = kmap(pp);
-           else {
-               /* rx doesn't provide an interface to simply advance
-                  or consume n bytes.  for now, allocate a PAGE_SIZE
-                  region of memory to receive bytes in the case that
-                  there were holes in readpages */
-               if(page_buffer == NULL)
-                   page_buffer = osi_Alloc(PAGE_SIZE);
-                   address = page_buffer;
-               }
-#else
            address = page_buffer;
-#endif
 #else
 #ifndef UKERNEL
 #error AFS_CACHE_BYPASS not implemented on this platform
@@ -411,13 +407,11 @@ afs_NoCacheFetchProc(struct rx_call *acall,
                address += code;
            } else {
 #ifdef AFS_LINUX24_ENV
-#ifdef AFS_KMAP_ATOMIC
                if(pp) {
                    address = kmap_atomic(pp, KM_USER0);
                    memcpy(address, page_buffer, PAGE_SIZE);
                    kunmap_atomic(address, KM_USER0);
                }
-#endif
 #else
 #ifndef UKERNEL
 #error AFS_CACHE_BYPASS not implemented on this platform
@@ -434,9 +428,6 @@ afs_NoCacheFetchProc(struct rx_call *acall,
                     else
                         afs_warn("afs_NoCacheFetchProc: page not locked at iovno %d!\n", iovno);
                     put_page(pp); /* decrement refcount */
-#ifndef AFS_KMAP_ATOMIC
-                    kunmap(pp);
-#endif
 #else
 #ifndef UKERNEL
 #error AFS_CACHE_BYPASS not implemented on this platform