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Fri, 21 Mar 2025 16:14:18 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.61]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 7507E1955BFE; Fri, 21 Mar 2025 16:14:15 +0000 (UTC) From: David Howells To: Leon Romanovsky Cc: David Howells , Christian Brauner , Matthew Wilcox , Chuck Lever , Steve French , Ilya Dryomov , netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 1/4] iov_iter: Move ITER_DISCARD and ITER_XARRAY iteration out-of-line Date: Fri, 21 Mar 2025 16:14:01 +0000 Message-ID: <20250321161407.3333724-2-dhowells@redhat.com> In-Reply-To: <20250321161407.3333724-1-dhowells@redhat.com> References: <20250321161407.3333724-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Rspamd-Queue-Id: 3DE2F40017 X-Stat-Signature: rt5zz54p46ieo3dr646b5h7f9uxf5e86 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1742573667-354348 X-HE-Meta: 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 x0v8+RPa tq/zysf0/lfX8DY+HsQNP2HqRN+YgA8VhF9tszgc3+4vYEjeNN8sQKBissfjzfX5aRjrGTVuoy935SCDTRtJ367DdML361B3gyuN0mwVtrC5BTdTYPMnBauI3Dj0if2NoVfa8JiAlhLBRqZbmDm4PWxeJCXdjxmnaoUIz0DLDP7jrYJlhwynX9/bb1RvYJNA4hrVf8eXLcY5dBnGNDO90efSRKkPq2cuTJ1PeweKDhupYL6vCNKIqgUIILEguyv11dyNDTWB8On1Hs4WVy8BGN7uqVbZi21gMsl8Vf/0EaPWae7ac/elZp17jj9OvmRHsYpUQQeWFITHbKFly7ebeIQ7LAXL50VO/LPGLVfBWa50FA2lks9eiXYIRxdMGhilD/QHV X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Move ITER_DISCARD and ITER_XARRAY iteration out-of-line in preparation of adding other iteration types which will also be out-of-line. Signed-off-by: David Howells --- include/linux/iov_iter.h | 77 +++----------------------------------- lib/iov_iter.c | 81 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+), 72 deletions(-) diff --git a/include/linux/iov_iter.h b/include/linux/iov_iter.h index c4aa58032faf..0c47933df517 100644 --- a/include/linux/iov_iter.h +++ b/include/linux/iov_iter.h @@ -17,6 +17,9 @@ typedef size_t (*iov_step_f)(void *iter_base, size_t progress, size_t len, typedef size_t (*iov_ustep_f)(void __user *iter_base, size_t progress, size_t len, void *priv, void *priv2); +size_t __iterate_and_advance2(struct iov_iter *iter, size_t len, void *priv, + void *priv2, iov_ustep_f ustep, iov_step_f step); + /* * Handle ITER_UBUF. */ @@ -195,72 +198,6 @@ size_t iterate_folioq(struct iov_iter *iter, size_t len, void *priv, void *priv2 return progress; } -/* - * Handle ITER_XARRAY. - */ -static __always_inline -size_t iterate_xarray(struct iov_iter *iter, size_t len, void *priv, void *priv2, - iov_step_f step) -{ - struct folio *folio; - size_t progress = 0; - loff_t start = iter->xarray_start + iter->iov_offset; - pgoff_t index = start / PAGE_SIZE; - XA_STATE(xas, iter->xarray, index); - - rcu_read_lock(); - xas_for_each(&xas, folio, ULONG_MAX) { - size_t remain, consumed, offset, part, flen; - - if (xas_retry(&xas, folio)) - continue; - if (WARN_ON(xa_is_value(folio))) - break; - if (WARN_ON(folio_test_hugetlb(folio))) - break; - - offset = offset_in_folio(folio, start + progress); - flen = min(folio_size(folio) - offset, len); - - while (flen) { - void *base = kmap_local_folio(folio, offset); - - part = min_t(size_t, flen, - PAGE_SIZE - offset_in_page(offset)); - remain = step(base, progress, part, priv, priv2); - kunmap_local(base); - - consumed = part - remain; - progress += consumed; - len -= consumed; - - if (remain || len == 0) - goto out; - flen -= consumed; - offset += consumed; - } - } - -out: - rcu_read_unlock(); - iter->iov_offset += progress; - iter->count -= progress; - return progress; -} - -/* - * Handle ITER_DISCARD. - */ -static __always_inline -size_t iterate_discard(struct iov_iter *iter, size_t len, void *priv, void *priv2, - iov_step_f step) -{ - size_t progress = len; - - iter->count -= progress; - return progress; -} - /** * iterate_and_advance2 - Iterate over an iterator * @iter: The iterator to iterate over. @@ -306,9 +243,7 @@ size_t iterate_and_advance2(struct iov_iter *iter, size_t len, void *priv, return iterate_kvec(iter, len, priv, priv2, step); if (iov_iter_is_folioq(iter)) return iterate_folioq(iter, len, priv, priv2, step); - if (iov_iter_is_xarray(iter)) - return iterate_xarray(iter, len, priv, priv2, step); - return iterate_discard(iter, len, priv, priv2, step); + return __iterate_and_advance2(iter, len, priv, priv2, ustep, step); } /** @@ -370,9 +305,7 @@ size_t iterate_and_advance_kernel(struct iov_iter *iter, size_t len, void *priv, return iterate_kvec(iter, len, priv, priv2, step); if (iov_iter_is_folioq(iter)) return iterate_folioq(iter, len, priv, priv2, step); - if (iov_iter_is_xarray(iter)) - return iterate_xarray(iter, len, priv, priv2, step); - return iterate_discard(iter, len, priv, priv2, step); + return __iterate_and_advance2(iter, len, priv, priv2, NULL, step); } #endif /* _LINUX_IOV_ITER_H */ diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 65f550cb5081..33a8746e593e 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1927,3 +1927,84 @@ ssize_t iov_iter_extract_pages(struct iov_iter *i, return -EFAULT; } EXPORT_SYMBOL_GPL(iov_iter_extract_pages); + +/* + * Handle ITER_XARRAY. + */ +static __always_inline +size_t iterate_xarray(struct iov_iter *iter, size_t len, void *priv, void *priv2, + iov_step_f step) +{ + struct folio *folio; + size_t progress = 0; + loff_t start = iter->xarray_start + iter->iov_offset; + pgoff_t index = start / PAGE_SIZE; + XA_STATE(xas, iter->xarray, index); + + rcu_read_lock(); + xas_for_each(&xas, folio, ULONG_MAX) { + size_t remain, consumed, offset, part, flen; + + if (xas_retry(&xas, folio)) + continue; + if (WARN_ON(xa_is_value(folio))) + break; + if (WARN_ON(folio_test_hugetlb(folio))) + break; + + offset = offset_in_folio(folio, start + progress); + flen = min(folio_size(folio) - offset, len); + + while (flen) { + void *base = kmap_local_folio(folio, offset); + + part = min_t(size_t, flen, + PAGE_SIZE - offset_in_page(offset)); + remain = step(base, progress, part, priv, priv2); + kunmap_local(base); + + consumed = part - remain; + progress += consumed; + len -= consumed; + + if (remain || len == 0) + goto out; + flen -= consumed; + offset += consumed; + } + } + +out: + rcu_read_unlock(); + iter->iov_offset += progress; + iter->count -= progress; + return progress; +} + +/* + * Handle ITER_DISCARD. + */ +static __always_inline +size_t iterate_discard(struct iov_iter *iter, size_t len, void *priv, void *priv2, + iov_step_f step) +{ + size_t progress = len; + + iter->count -= progress; + return progress; +} + +/* + * Out of line iteration for iterator types that don't need such fast handling. + */ +size_t __iterate_and_advance2(struct iov_iter *iter, size_t len, void *priv, + void *priv2, iov_ustep_f ustep, iov_step_f step) +{ + if (iov_iter_is_discard(iter)) + return iterate_discard(iter, len, priv, priv2, step); + if (iov_iter_is_xarray(iter)) + return iterate_xarray(iter, len, priv, priv2, step); + WARN_ON(1); + return 0; +} +EXPORT_SYMBOL(__iterate_and_advance2);