Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965119AbVIIJVV (ORCPT ); Fri, 9 Sep 2005 05:21:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965121AbVIIJVV (ORCPT ); Fri, 9 Sep 2005 05:21:21 -0400 Received: from ppsw-1.csi.cam.ac.uk ([131.111.8.131]:40130 "EHLO ppsw-1.csi.cam.ac.uk") by vger.kernel.org with ESMTP id S965119AbVIIJVU (ORCPT ); Fri, 9 Sep 2005 05:21:20 -0400 X-Cam-SpamDetails: Not scanned X-Cam-AntiVirus: No virus found X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ Date: Fri, 9 Sep 2005 10:21:18 +0100 (BST) From: Anton Altaparmakov To: Linus Torvalds cc: linux-kernel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net Subject: [PATCH 3/25] NTFS: Use ntfs_malloc_nofs_nofail() in ntfs_runlists_merge(). In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4719 Lines: 137 [PATCH 3/25] NTFS: Use ntfs_malloc_nofs_nofail() in ntfs_runlists_merge() in the two critical regions. This means we no longer need to panic() when the allocation fails as it now cannot fail. Signed-off-by: Anton Altaparmakov --- fs/ntfs/ChangeLog | 3 ++ fs/ntfs/runlist.c | 68 +++++++++++++++++++++++++++++++++++++++-------------- 2 files changed, 53 insertions(+), 18 deletions(-) 9529d461d0992959026264b8fc002ac01d226708 diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog --- a/fs/ntfs/ChangeLog +++ b/fs/ntfs/ChangeLog @@ -40,6 +40,9 @@ ToDo/Notes: - Add fs/ntfs/malloc.h::ntfs_malloc_nofs_nofail() which is analogous to ntfs_malloc_nofs() but it performs allocations with __GFP_NOFAIL and hence cannot fail. + - Use ntfs_malloc_nofs_nofail() in the two critical regions in + fs/ntfs/runlist.c::ntfs_runlists_merge(). This means we no longer + need to panic() if the allocation fails as it now cannot fail. 2.1.23 - Implement extension of resident files and make writing safe as well as many bug fixes, cleanups, and enhancements... diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c --- a/fs/ntfs/runlist.c +++ b/fs/ntfs/runlist.c @@ -35,7 +35,7 @@ static inline void ntfs_rl_mm(runlist_el int size) { if (likely((dst != src) && (size > 0))) - memmove(base + dst, base + src, size * sizeof (*base)); + memmove(base + dst, base + src, size * sizeof(*base)); } /** @@ -95,6 +95,51 @@ static inline runlist_element *ntfs_rl_r } /** + * ntfs_rl_realloc_nofail - Reallocate memory for runlists + * @rl: original runlist + * @old_size: number of runlist elements in the original runlist @rl + * @new_size: number of runlist elements we need space for + * + * As the runlists grow, more memory will be required. To prevent the + * kernel having to allocate and reallocate large numbers of small bits of + * memory, this function returns an entire page of memory. + * + * This function guarantees that the allocation will succeed. It will sleep + * for as long as it takes to complete the allocation. + * + * It is up to the caller to serialize access to the runlist @rl. + * + * N.B. If the new allocation doesn't require a different number of pages in + * memory, the function will return the original pointer. + * + * On success, return a pointer to the newly allocated, or recycled, memory. + * On error, return -errno. The following error codes are defined: + * -ENOMEM - Not enough memory to allocate runlist array. + * -EINVAL - Invalid parameters were passed in. + */ +static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl, + int old_size, int new_size) +{ + runlist_element *new_rl; + + old_size = PAGE_ALIGN(old_size * sizeof(*rl)); + new_size = PAGE_ALIGN(new_size * sizeof(*rl)); + if (old_size == new_size) + return rl; + + new_rl = ntfs_malloc_nofs_nofail(new_size); + BUG_ON(!new_rl); + + if (likely(rl != NULL)) { + if (unlikely(old_size > new_size)) + old_size = new_size; + memcpy(new_rl, rl, old_size); + ntfs_free(rl); + } + return new_rl; +} + +/** * ntfs_are_rl_mergeable - test if two runlists can be joined together * @dst: original runlist * @src: new runlist to test for mergeability with @dst @@ -621,11 +666,8 @@ runlist_element *ntfs_runlists_merge(run if (drl[ds].lcn != LCN_RL_NOT_MAPPED) { /* Add an unmapped runlist element. */ if (!slots) { - /* FIXME/TODO: We need to have the - * extra memory already! (AIA) */ - drl = ntfs_rl_realloc(drl, ds, ds + 2); - if (!drl) - goto critical_error; + drl = ntfs_rl_realloc_nofail(drl, ds, + ds + 2); slots = 2; } ds++; @@ -640,13 +682,8 @@ runlist_element *ntfs_runlists_merge(run drl[ds].length = marker_vcn - drl[ds].vcn; /* Finally add the ENOENT terminator. */ ds++; - if (!slots) { - /* FIXME/TODO: We need to have the extra - * memory already! (AIA) */ - drl = ntfs_rl_realloc(drl, ds, ds + 1); - if (!drl) - goto critical_error; - } + if (!slots) + drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1); drl[ds].vcn = marker_vcn; drl[ds].lcn = LCN_ENOENT; drl[ds].length = (s64)0; @@ -659,11 +696,6 @@ finished: ntfs_debug("Merged runlist:"); ntfs_debug_dump_runlist(drl); return drl; - -critical_error: - /* Critical error! We cannot afford to fail here. */ - ntfs_error(NULL, "Critical error! Not enough memory."); - panic("NTFS: Cannot continue."); } /** - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/