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Thu, 6 Aug 2026 18:09:58 +0000 (GMT) Date: Thu, 6 Aug 2026 20:09:57 +0200 From: Heiko Carstens To: Bart Van Assche Cc: Jens Axboe , Stefan Haberland , Jan =?iso-8859-1?Q?H=F6ppner?= , linux-s390@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH 1/2] s390/dasd: Add __context_unsafe() attribute to various functions Message-ID: <20260806180957.10725Aa3-hca@linux.ibm.com> References: <20260806130050.2057443-1-hca@linux.ibm.com> <20260806130050.2057443-2-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=G6ws1dk5 c=1 sm=1 tr=0 ts=6a74cdfb cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=kj9zAlcOel0A:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=Evt7RIZt8xg5G9nE-bcA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA2MDEzOSBTYWx0ZWRfX3NqyvceSh6v1 kd+ZG5Tv5HPw0v5nAlie389a3iin8dv1f2+pqA8RrUriUx7bstEumq6AkuVbEw9t+SMKpQ+4Gwb JDdceBnHxkhtIzDkIKrB0Y7avKC20udr4eDZ21QbzbGTKn/L20Tt9PUIRBPnCX4v2pCNuPVaGVK jSK/gmxrPZbB0uAOoK5Aa5dmohxDDG4MoX2Op9xc0V3PSEfFHa06irGIMNoEeK29ScRKVyGv47v QGjKJe0NrGDgzoU9rYBhdHCMWlpmqOizKqDTS2hy95xCDRC0O7MGRSXgyOx0TSyCbv4WTIkpVCi yPANssn96YrMMhRfHFOVwmapow/Y6NcmKETH39idWPRXN2olV21aGEYgvpxTJqxP0R4bafv3DpP qoSqBe1yLPYuISGlu3ty8ofc9tHsOciGvBg9jfm6Ke/ctopt+JX2W17X26os7Ee7zaZzVbUFEs6 Ym3StD3YgIlcZaRH6Iw== X-Proofpoint-ORIG-GUID: 0pqVgmyWNXbanQKBnirEFO8SxwQY8-6U X-Proofpoint-Spam-Info: AW1haW4tMjYwODA2MDEzOSBTYWx0ZWRfX6fzTZ5QKBktN CeUp/pN3yHXSupXQSbGVHxoqxoGuNjk9/t6DrqzetAiMGI5tXxY2CZiiBik3+jA6xwTCd25pJ3V 2eVUPLVAairn/RtJuUN0WrZpsoezvHo= X-Proofpoint-GUID: 0pqVgmyWNXbanQKBnirEFO8SxwQY8-6U X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-06_01,2026-08-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 spamscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 phishscore=0 priorityscore=1501 adultscore=0 bulkscore=0 clxscore=1011 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608060139 On Thu, Aug 06, 2026 at 09:34:06AM -0700, Bart Van Assche wrote: > On 8/6/26 6:00 AM, Heiko Carstens wrote: > > diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c > > index bacf770c0e1f..b4dcef06edaa 100644 > > --- a/drivers/s390/block/dasd_eckd.c > > +++ b/drivers/s390/block/dasd_eckd.c > > @@ -1468,6 +1468,7 @@ static void dasd_eckd_path_available_action(struct dasd_device *device, > > } > > static void do_pe_handler_work(struct work_struct *work) > > +__context_unsafe(/* Conditional locking */) > > { > > struct pe_handler_work_data *data; > > struct dasd_device *device; > > __context_unsafe() should be avoided if there is a better solution. Sure, I did that for other code, but this one is up to Stefan. > For > this driver I propose to make the following changes: > - Change dasd_pe_handler_mutex into a semaphore. This driver locks this > mutex from one kernel thread and unlocks it from another kernel > thread. That's not allowed! Yes, I did not realize that when adding those attributes, however that was also reported by Sashiko. > - Split the dasd_eckd_read_vol_info(), dasd_eckd_release(), ... > functions. Move the code between the mutex_lock() and mutex_unlock() > calls into a new function. Rework both functions such that the > mutex_lock() and mutex_unlock() calls end up in the same branch of an > if-statement. Agreed, all for Stefan's todo list :)