Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[deliverable/linux.git] / fs / cifs / connect.c

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0ae86ddf22138180383542548b3fb7e003c94453..94b7788c3189281e043ecf82b9bf4fb1e9d0e0f7 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3445,6 +3445,18 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 #define CIFS_DEFAULT_NON_POSIX_RSIZE (60 * 1024)
 #define CIFS_DEFAULT_NON_POSIX_WSIZE (65536)
 
+/*
+ * On hosts with high memory, we can't currently support wsize/rsize that are
+ * larger than we can kmap at once. Cap the rsize/wsize at
+ * LAST_PKMAP * PAGE_SIZE. We'll never be able to fill a read or write request
+ * larger than that anyway.
+ */
+#ifdef CONFIG_HIGHMEM
+#define CIFS_KMAP_SIZE_LIMIT   (LAST_PKMAP * PAGE_CACHE_SIZE)
+#else /* CONFIG_HIGHMEM */
+#define CIFS_KMAP_SIZE_LIMIT   (1<<24)
+#endif /* CONFIG_HIGHMEM */
+
 static unsigned int
 cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
 {
@@ -3475,6 +3487,9 @@ cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
                wsize = min_t(unsigned int, wsize,
                                server->maxBuf - sizeof(WRITE_REQ) + 4);
 
+       /* limit to the amount that we can kmap at once */
+       wsize = min_t(unsigned int, wsize, CIFS_KMAP_SIZE_LIMIT);
+
        /* hard limit of CIFS_MAX_WSIZE */
        wsize = min_t(unsigned int, wsize, CIFS_MAX_WSIZE);
 
@@ -3516,6 +3531,9 @@ cifs_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
        if (!(server->capabilities & CAP_LARGE_READ_X))
                rsize = min_t(unsigned int, CIFSMaxBufSize, rsize);
 
+       /* limit to the amount that we can kmap at once */
+       rsize = min_t(unsigned int, rsize, CIFS_KMAP_SIZE_LIMIT);
+
        /* hard limit of CIFS_MAX_RSIZE */
        rsize = min_t(unsigned int, rsize, CIFS_MAX_RSIZE);