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sagi@grimberg.me, jejb@linux.ibm.com, martin.petersen@oracle.com, djwong@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, chandan.babu@oracle.com, dchinner@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com, linux-api@vger.kernel.org, Himanshu Madhani References: <20230929102726.2985188-1-john.g.garry@oracle.com> <20230929102726.2985188-2-john.g.garry@oracle.com> <20231109151013.GA32432@lst.de> From: John Garry Organization: Oracle Corporation In-Reply-To: <20231109151013.GA32432@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: LNXP265CA0006.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:5e::18) To DM6PR10MB4313.namprd10.prod.outlook.com (2603:10b6:5:212::20) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 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b8qYzLyHgHjBM/zvNAns3zKiJHqR6N218el6wK17aevcMGRo4T/hMuU0NDucbBJNcOjEtrlt1IEpRCcf0b4efw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR10MB6080 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-09_14,2023-11-09_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 suspectscore=0 malwarescore=0 mlxlogscore=999 bulkscore=0 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311060000 definitions=main-2311090129 X-Proofpoint-ORIG-GUID: KRBFPtmvSldNnwAJavlQI07toVo6ZhHh X-Proofpoint-GUID: KRBFPtmvSldNnwAJavlQI07toVo6ZhHh On 09/11/2023 15:10, Christoph Hellwig wrote: >> Documentation/ABI/stable/sysfs-block | 42 +++++++++++++++++++ >> block/blk-settings.c | 60 ++++++++++++++++++++++++++++ >> block/blk-sysfs.c | 33 +++++++++++++++ >> include/linux/blkdev.h | 33 +++++++++++++++ >> 4 files changed, 168 insertions(+) >> >> diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block >> index 1fe9a553c37b..05df7f74cbc1 100644 >> --- a/Documentation/ABI/stable/sysfs-block >> +++ b/Documentation/ABI/stable/sysfs-block >> @@ -21,6 +21,48 @@ Description: >> device is offset from the internal allocation unit's >> natural alignment. >> >> +What: /sys/block//atomic_write_max_bytes >> +Date: May 2023 >> +Contact: Himanshu Madhani >> +Description: >> + [RO] This parameter specifies the maximum atomic write >> + size reported by the device. An atomic write operation >> + must not exceed this number of bytes. >> +What: /sys/block//atomic_write_unit_max_bytes >> +Date: January 2023 >> +Contact: Himanshu Madhani >> +Description: >> + [RO] This parameter defines the largest block which can be >> + written atomically with an atomic write operation. This >> + value must be a multiple of atomic_write_unit_min and must >> + be a power-of-two. > What is the difference between these two values? Generally they come from the same device property. Then since atomic_write_unit_max_bytes must be a power-of-2 (and atomic_write_max_bytes may not be), they may be different. In addition, atomic_write_unit_max_bytes is required to be limited by whatever is guaranteed to be able to fit in a bio. atomic_write_max_bytes is really only relevant for merging writes. Maybe we should not even expose via sysfs. BTW, I do still wonder whether all these values should be limited by max_sectors_kb (which they aren't currently). > > >> +Date: May 2023 >> +Contact: Himanshu Madhani >> +Description: >> + [RO] This parameter specifies the smallest block which can >> + be written atomically with an atomic write operation. All >> + atomic write operations must begin at a >> + atomic_write_unit_min boundary and must be multiples of >> + atomic_write_unit_min. This value must be a power-of-two. > How can the minimum unit be anythіng but one logical block? > >> +extern void blk_queue_atomic_write_max_bytes(struct request_queue *q, >> + unsigned int bytes); > Please don't add pointless externs to prototypes in headers. ok, fine - blkdev.h seems to have a mix for declarations with and without extern, so at least we would be consistently inconsistent. > >> +static inline unsigned int queue_atomic_write_unit_max_bytes(const struct request_queue *q) > .. and please avoid the overly long lines. ok Thanks, John >