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bh=gfSLwCbdFMwywMZPFTO5hx480mND9O9O9B3C6PwfVhs=; b=M7yuaAEgK3qs9gftqg8WBpT4KwPOSPwYyuojEW8l+JMt3yVRAMvdazx/1MZSMNaWvPNC98 JhHkUPH7+WCFieAydxUac4r8Q1nWy9W6wNG6Q8AuyvURkhNYo7Ptavr/kvN4TZ61hl4y16 I+c9MBnHvWREgvPmXfHwMcDre19WvIE= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-136-d7Mhfh32MBiW5Kow5NUZRQ-1; Fri, 22 Sep 2023 08:02:53 -0400 X-MC-Unique: d7Mhfh32MBiW5Kow5NUZRQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 533BA1C0172F; Fri, 22 Sep 2023 12:02:52 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.216]) by smtp.corp.redhat.com (Postfix) with ESMTP id ADFF220268D6; Fri, 22 Sep 2023 12:02:50 +0000 (UTC) From: David Howells To: Jens Axboe Cc: David Howells , Al Viro , Linus Torvalds , Christoph Hellwig , Christian Brauner , David Laight , Matthew Wilcox , Jeff Layton , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 08/13] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() Date: Fri, 22 Sep 2023 13:02:22 +0100 Message-ID: <20230922120227.1173720-9-dhowells@redhat.com> In-Reply-To: <20230922120227.1173720-1-dhowells@redhat.com> References: <20230922120227.1173720-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Rspamd-Queue-Id: 245F3C0010 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: nspiq5jb753fbs385r75j5ua1phrihwq X-HE-Tag: 1695384175-918973 X-HE-Meta: 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 +v0ySPOz mIEVrTU2C7pmlfK1IcTHTrdqWOpQ+1eYIPnpnkPxkrhn1iShaI2MezvJi8gkgR418vkl+ntEdrqoDQjHWi6HCC8fzTtfjkw4neauSMRDnyqqMsTfNoNGC98GmrSD1ju15hVelu4hgXQYkYFIgRdeJEtWZOPt2oZmKg/+78rnotukWdp37FYZW+NSmxXpkV1XFIexQ 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: iter->copy_mc is only used with a bvec iterator and only by dump_emit_page() in fs/coredump.c so rather than handle this in memcpy_from_iter_mc() where it is checked repeatedly by _copy_from_iter() and copy_page_from_iter_atomic(), --- lib/iov_iter.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 65374ee91ecd..943aa3cfd7b3 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -253,14 +253,33 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) EXPORT_SYMBOL_GPL(_copy_mc_to_iter); #endif /* CONFIG_ARCH_HAS_COPY_MC */ -static size_t memcpy_from_iter_mc(void *iter_from, size_t progress, - size_t len, void *to, void *priv2) +static __always_inline +size_t memcpy_from_iter_mc(void *iter_from, size_t progress, + size_t len, void *to, void *priv2) +{ + return copy_mc_to_kernel(to + progress, iter_from, len); +} + +static size_t __copy_from_iter_mc(void *addr, size_t bytes, struct iov_iter *i) { - struct iov_iter *iter = priv2; + size_t progress; - if (iov_iter_is_copy_mc(iter)) - return copy_mc_to_kernel(to + progress, iter_from, len); - return memcpy_from_iter(iter_from, progress, len, to, priv2); + if (unlikely(i->count < bytes)) + bytes = i->count; + if (unlikely(!bytes)) + return 0; + progress = iterate_bvec(i, bytes, addr, NULL, memcpy_from_iter_mc); + i->count -= progress; + return progress; +} + +static __always_inline +size_t __copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) +{ + if (unlikely(iov_iter_is_copy_mc(i))) + return __copy_from_iter_mc(addr, bytes, i); + return iterate_and_advance(i, bytes, addr, + copy_from_user_iter, memcpy_from_iter); } size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) @@ -270,9 +289,7 @@ size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) if (user_backed_iter(i)) might_fault(); - return iterate_and_advance2(i, bytes, addr, i, - copy_from_user_iter, - memcpy_from_iter_mc); + return __copy_from_iter(addr, bytes, i); } EXPORT_SYMBOL(_copy_from_iter); @@ -493,9 +510,7 @@ size_t copy_page_from_iter_atomic(struct page *page, size_t offset, } p = kmap_atomic(page) + offset; - n = iterate_and_advance2(i, n, p, i, - copy_from_user_iter, - memcpy_from_iter_mc); + __copy_from_iter(p, n, i); kunmap_atomic(p); copied += n; offset += n;