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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jlOzF1QhqikCoQxsvfJV6M6Hjgbrow9dB9uNs1AoGLE=; b=g0sLQkOcusUBdVp7RO8L1CIHeE4b/dxDRQevN3sEDMG+dpbQjRykf7SSXIYR8bMnyk 5SJ25xjieVKXKzElQ3KE0qu2EXc1TZ9MFXryc0mRtPRI1jz0lAY9L1UifHZPju/4k1jJ vueJNLhHsE8Bmce/8hPtKj1A9tWiWZbF2I/gOfo6kPNX+Ubh1AE+Hdf4hNhNFSihsLeH pXY2wxSmCHBV4gUcC2akyXdAoj6bAvi8FQdTe+9x0pxvJ6JzXLiFhyUfx3ETCI68cj5f ok21N8RADiZfjsRVHxYHROIK9Ti9njOneBlmqcpRnGchgMEgJbje/11cYRobfiNeKg+O ocSQ== X-Gm-Message-State: AOAM530wRCVBa7bVjSWkTFE4B58Lv49rU+WHU9lJoLfZ2Hcp9bp16RFI UsxNdQEmoLM1+uMcQ/HxWjM0ZH9FytW3OodK31WWCg== X-Google-Smtp-Source: ABdhPJxGxhMZ7o2BYtIDXOupUr3pSHVXck0tIwC9HMZ0nIbp0pU6AQKRljKqMwVkoxmX0BYp74elTVEnpYvo3LWFH24= X-Received: by 2002:a17:906:7e47:: with SMTP id z7mr1390518ejr.418.1602618108255; Tue, 13 Oct 2020 12:41:48 -0700 (PDT) MIME-Version: 1.0 References: <20201009195033.3208459-1-ira.weiny@intel.com> <20201009195033.3208459-34-ira.weiny@intel.com> <20201013193643.GK20115@casper.infradead.org> In-Reply-To: <20201013193643.GK20115@casper.infradead.org> From: Dan Williams Date: Tue, 13 Oct 2020 12:41:36 -0700 Message-ID: Subject: Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread() To: Matthew Wilcox X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201013_154151_538275_EAF01EE2 X-CRM114-Status: GOOD ( 25.10 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-efi , KVM list , Linux Doc Mailing List , Peter Zijlstra , linux-mmc@vger.kernel.org, Dave Hansen , Maling list - DRI developers , Linux MM , target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kselftest@vger.kernel.org, samba-technical@lists.samba.org, "Weiny, Ira" , ceph-devel@vger.kernel.org, drbd-dev@lists.linbit.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi , linux-nvdimm , linux-rdma , X86 ML , amd-gfx list , io-uring@vger.kernel.org, cluster-devel@redhat.com, Ingo Molnar , intel-wired-lan@lists.osuosl.org, xen-devel , linux-ext4 , Fenghua Yu , linux-afs@lists.infradead.org, linux-um@lists.infradead.org, intel-gfx@lists.freedesktop.org, ecryptfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, reiserfs-devel@vger.kernel.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, Borislav Petkov , Andy Lutomirski , Thomas Gleixner , Andrew Morton , linux-cachefs@redhat.com, linux-nfs@vger.kernel.org, Nicolas Pitre , linux-ntfs-dev@lists.sourceforge.net, Netdev , Kexec Mailing List , Linux Kernel Mailing List , linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel , bpf@vger.kernel.org, linuxppc-dev , linux-btrfs Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Tue, Oct 13, 2020 at 12:37 PM Matthew Wilcox wrote: > > On Tue, Oct 13, 2020 at 11:44:29AM -0700, Dan Williams wrote: > > On Fri, Oct 9, 2020 at 12:52 PM wrote: > > > > > > From: Ira Weiny > > > > > > The kmap() calls in this FS are localized to a single thread. To avoid > > > the over head of global PKRS updates use the new kmap_thread() call. > > > > > > Cc: Nicolas Pitre > > > Signed-off-by: Ira Weiny > > > --- > > > fs/cramfs/inode.c | 10 +++++----- > > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > > > diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c > > > index 912308600d39..003c014a42ed 100644 > > > --- a/fs/cramfs/inode.c > > > +++ b/fs/cramfs/inode.c > > > @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset, > > > struct page *page = pages[i]; > > > > > > if (page) { > > > - memcpy(data, kmap(page), PAGE_SIZE); > > > - kunmap(page); > > > + memcpy(data, kmap_thread(page), PAGE_SIZE); > > > + kunmap_thread(page); > > > > Why does this need a sleepable kmap? This looks like a textbook > > kmap_atomic() use case. > > There's a lot of code of this form. Could we perhaps have: > > static inline void copy_to_highpage(struct page *to, void *vfrom, unsigned int size) > { > char *vto = kmap_atomic(to); > > memcpy(vto, vfrom, size); > kunmap_atomic(vto); > } > > in linux/highmem.h ? Nice, yes, that could also replace the local ones in lib/iov_iter.c (memcpy_{to,from}_page()) ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/