# git rev-parse -q --verify 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b^{commit}
38e7571c07be01f9f19b355a9306a4e3d5cb0f5b
already have revision, skipping fetch
# git checkout -q -f -B kisskb 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b
# git clean -qxdf
# < git log -1
# commit 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b
# Merge: 80201fe175cb 21b4aa5d20fd
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Fri Mar 8 14:48:40 2019 -0800
# 
#     Merge tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block
#     
#     Pull io_uring IO interface from Jens Axboe:
#      "Second attempt at adding the io_uring interface.
#     
#       Since the first one, we've added basic unit testing of the three
#       system calls, that resides in liburing like the other unit tests that
#       we have so far. It'll take a while to get full coverage of it, but
#       we're working towards it. I've also added two basic test programs to
#       tools/io_uring. One uses the raw interface and has support for all the
#       various features that io_uring supports outside of standard IO, like
#       fixed files, fixed IO buffers, and polled IO. The other uses the
#       liburing API, and is a simplified version of cp(1).
#     
#       This adds support for a new IO interface, io_uring.
#     
#       io_uring allows an application to communicate with the kernel through
#       two rings, the submission queue (SQ) and completion queue (CQ) ring.
#       This allows for very efficient handling of IOs, see the v5 posting for
#       some basic numbers:
#     
#         https://lore.kernel.org/linux-block/20190116175003.17880-1-axboe@kernel.dk/
#     
#       Outside of just efficiency, the interface is also flexible and
#       extendable, and allows for future use cases like the upcoming NVMe
#       key-value store API, networked IO, and so on. It also supports async
#       buffered IO, something that we've always failed to support in the
#       kernel.
#     
#       Outside of basic IO features, it supports async polled IO as well.
#       This particular feature has already been tested at Facebook months ago
#       for flash storage boxes, with 25-33% improvements. It makes polled IO
#       actually useful for real world use cases, where even basic flash sees
#       a nice win in terms of efficiency, latency, and performance. These
#       boxes were IOPS bound before, now they are not.
#     
#       This series adds three new system calls. One for setting up an
#       io_uring instance (io_uring_setup(2)), one for submitting/completing
#       IO (io_uring_enter(2)), and one for aux functions like registrating
#       file sets, buffers, etc (io_uring_register(2)). Through the help of
#       Arnd, I've coordinated the syscall numbers so merge on that front
#       should be painless.
#     
#       Jon did a writeup of the interface a while back, which (except for
#       minor details that have been tweaked) is still accurate. Find that
#       here:
#     
#         https://lwn.net/Articles/776703/
#     
#       Huge thanks to Al Viro for helping getting the reference cycle code
#       correct, and to Jann Horn for his extensive reviews focused on both
#       security and bugs in general.
#     
#       There's a userspace library that provides basic functionality for
#       applications that don't need or want to care about how to fiddle with
#       the rings directly. It has helpers to allow applications to easily set
#       up an io_uring instance, and submit/complete IO through it without
#       knowing about the intricacies of the rings. It also includes man pages
#       (thanks to Jeff Moyer), and will continue to grow support helper
#       functions and features as time progresses. Find it here:
#     
#         git://git.kernel.dk/liburing
#     
#       Fio has full support for the raw interface, both in the form of an IO
#       engine (io_uring), but also with a small test application (t/io_uring)
#       that can exercise and benchmark the interface"
#     
#     * tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block:
#       io_uring: add a few test tools
#       io_uring: allow workqueue item to handle multiple buffered requests
#       io_uring: add support for IORING_OP_POLL
#       io_uring: add io_kiocb ref count
#       io_uring: add submission polling
#       io_uring: add file set registration
#       net: split out functions related to registering inflight socket files
#       io_uring: add support for pre-mapped user IO buffers
#       block: implement bio helper to add iter bvec pages to bio
#       io_uring: batch io_kiocb allocation
#       io_uring: use fget/fput_many() for file references
#       fs: add fget_many() and fput_many()
#       io_uring: support for IO polling
#       io_uring: add fsync support
#       Add io_uring IO interface
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-ld --version
# < git log --format=%s --max-count=1 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b
# < make -s -j 48 ARCH=arm O=/kisskb/build/linus_magician_defconfig_arm CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-  magician_defconfig
# make -s -j 48 ARCH=arm O=/kisskb/build/linus_magician_defconfig_arm CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-  
<stdin>:1478:2: warning: #warning syscall io_uring_setup not implemented [-Wcpp]
<stdin>:1481:2: warning: #warning syscall io_uring_enter not implemented [-Wcpp]
<stdin>:1484:2: warning: #warning syscall io_uring_register not implemented [-Wcpp]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c: In function 'init_srcu_struct_fields':
/kisskb/src/kernel/rcu/srcutree.c:121:34: warning: 'levelspread[<U8500>]' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c:88:6: note: 'levelspread[<U8500>]' was declared here
/kisskb/src/drivers/i2c/i2c-core-base.c: In function 'i2c_generic_scl_recovery':
/kisskb/src/drivers/i2c/i2c-core-base.c:235:5: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:339:21: note: 'pdeo' was declared here
/kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read':
/kisskb/src/drivers/base/regmap/regmap.c:2594:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write':
/kisskb/src/drivers/base/regmap/regmap.c:1855:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv4/ip_output.c: In function '__ip_append_data':
/kisskb/src/include/linux/skbuff.h:1343:6: warning: 'extra_uref' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv4/ip_output.c:885:14: note: 'extra_uref' was declared here
Completed OK
# rm -rf /kisskb/build/linus_magician_defconfig_arm
# Build took: 0:00:34.924537