Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933910Ab3CHW6M (ORCPT ); Fri, 8 Mar 2013 17:58:12 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:30406 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758124Ab3CHWwq (ORCPT ); Fri, 8 Mar 2013 17:52:46 -0500 From: Dave Kleikamp To: Zach Brown Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Dave Kleikamp Subject: [PATCH V7 -next 09/33] iov_iter: add a shorten call Date: Fri, 8 Mar 2013 16:52:04 -0600 Message-Id: <1362783148-22736-10-git-send-email-dave.kleikamp@oracle.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1362783148-22736-1-git-send-email-dave.kleikamp@oracle.com> References: <1362783148-22736-1-git-send-email-dave.kleikamp@oracle.com> X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3379 Lines: 97 From: Zach Brown The generic direct write path wants to shorten its memory vector. It does this when it finds that it has to perform a partial write due to LIMIT_FSIZE. .direct_IO() always performs IO on all of the referenced memory because it doesn't have an argument to specify the length of the IO. We add an iov_iter operation for this so that the generic path can ask to shorten the memory vector without having to know what kind it is. We're happy to shorten the kernel copy of the iovec array, but we refuse to shorten the bio_vec array and return an error in this case. Signed-off-by: Dave Kleikamp Cc: Zach Brown --- fs/iov-iter.c | 15 +++++++++++++++ include/linux/fs.h | 5 +++++ 2 files changed, 20 insertions(+) diff --git a/fs/iov-iter.c b/fs/iov-iter.c index 5624e36..ec461c8 100644 --- a/fs/iov-iter.c +++ b/fs/iov-iter.c @@ -226,6 +226,11 @@ static size_t ii_bvec_single_seg_count(const struct iov_iter *i) return min(i->count, bvec->bv_len - i->iov_offset); } +static int ii_bvec_shorten(struct iov_iter *i, size_t count) +{ + return -EINVAL; +} + struct iov_iter_ops ii_bvec_ops = { .ii_copy_to_user_atomic = ii_bvec_copy_to_user_atomic, .ii_copy_to_user = ii_bvec_copy_to_user, @@ -234,6 +239,7 @@ struct iov_iter_ops ii_bvec_ops = { .ii_advance = ii_bvec_advance, .ii_fault_in_readable = ii_bvec_fault_in_readable, .ii_single_seg_count = ii_bvec_single_seg_count, + .ii_shorten = ii_bvec_shorten, }; EXPORT_SYMBOL(ii_bvec_ops); #endif /* CONFIG_BLOCK */ @@ -384,6 +390,14 @@ static size_t ii_iovec_single_seg_count(const struct iov_iter *i) return min(i->count, iov->iov_len - i->iov_offset); } +static int ii_iovec_shorten(struct iov_iter *i, size_t count) +{ + struct iovec *iov = (struct iovec *)i->data; + i->nr_segs = iov_shorten(iov, i->nr_segs, count); + i->count = min(i->count, count); + return 0; +} + struct iov_iter_ops ii_iovec_ops = { .ii_copy_to_user_atomic = ii_iovec_copy_to_user_atomic, .ii_copy_to_user = ii_iovec_copy_to_user, @@ -392,5 +406,6 @@ struct iov_iter_ops ii_iovec_ops = { .ii_advance = ii_iovec_advance, .ii_fault_in_readable = ii_iovec_fault_in_readable, .ii_single_seg_count = ii_iovec_single_seg_count, + .ii_shorten = ii_iovec_shorten, }; EXPORT_SYMBOL(ii_iovec_ops); diff --git a/include/linux/fs.h b/include/linux/fs.h index a30d174..bd15cdb 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -308,6 +308,7 @@ struct iov_iter_ops { void (*ii_advance)(struct iov_iter *, size_t); int (*ii_fault_in_readable)(struct iov_iter *, size_t); size_t (*ii_single_seg_count)(const struct iov_iter *); + int (*ii_shorten)(struct iov_iter *, size_t); }; static inline size_t iov_iter_copy_to_user_atomic(struct page *page, @@ -347,6 +348,10 @@ static inline size_t iov_iter_single_seg_count(const struct iov_iter *i) { return i->ops->ii_single_seg_count(i); } +static inline int iov_iter_shorten(struct iov_iter *i, size_t count) +{ + return i->ops->ii_shorten(i, count); +} #ifdef CONFIG_BLOCK extern struct iov_iter_ops ii_bvec_ops; -- 1.8.1.5 -- 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/