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authorZeng Chi <zengchi@kylinos.cn>2026-09-21 18:24:42 +0800
committerSean Christopherson <seanjc@google.com>2026-09-22 08:36:16 -0700
commit119e9db233ad0f4cbd4cfb9f9385a7bca378b37d (patch)
tree660d50d4139cb750fbde1ae3432452c20726c99d /Documentation/ABI/testing/sysfs-block-loop
downloadlinux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.tar.gz
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KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted
Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson <seanjc@google.com> Cc: David Ballesteros <davimaba.v@proton.me> Signed-off-by: Zeng Chi <zengchi@kylinos.cn> Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson <seanjc@google.com>
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+What: /sys/block/loopX/loop/autoclear
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Shows if the device is in autoclear mode or not ( "1" or
+ "0"). Autoclear (if set) indicates that the loopback device will
+ self-distruct after last close.
+
+What: /sys/block/loopX/loop/backing_file
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) The path of the backing file that the loop device maps its
+ data blocks to.
+
+What: /sys/block/loopX/loop/offset
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Start offset (in bytes).
+
+What: /sys/block/loopX/loop/sizelimit
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) The size (in bytes) that the block device maps, starting
+ from the offset.
+
+What: /sys/block/loopX/loop/partscan
+Date: Aug, 2011
+KernelVersion: v3.10
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Shows if automatic partition scanning is enabled for the
+ device or not ("1" or "0"). This can be requested individually
+ per loop device during its setup by setting LO_FLAGS_PARTSCAN in
+ in the ioctl request. By default, no partition tables are
+ scanned.
+
+What: /sys/block/loopX/loop/dio
+Date: Aug, 2015
+KernelVersion: v4.10
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Shows if direct IO is being used to access backing file or
+ not ("1 or "0").