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Petersen" , Johannes Thumshirn Subject: [PATCH v2 06/15] blktrace: split do_blk_trace_setup into two functions Date: Thu, 25 Sep 2025 17:02:22 +0200 Message-ID: <20250925150231.67342-7-johannes.thumshirn@wdc.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250925150231.67342-1-johannes.thumshirn@wdc.com> References: <20250925150231.67342-1-johannes.thumshirn@wdc.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Split do_blk_trace_setup into two functions, this is done to prepare for an incoming new BLKTRACESETUP2 ioctl(2) which can receive extended parameters form user-space. Also move the size verification logic to the callers. Signed-off-by: Johannes Thumshirn Reviewed-by: Damien Le Moal --- kernel/trace/blktrace.c | 95 ++++++++++++++++++++++++----------------- 1 file changed, 57 insertions(+), 38 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 51c001e4981c..f6a41e9510f6 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -518,9 +518,10 @@ static void blk_trace_setup_lba(struct blk_trace *bt, /* * Setup everything required to start tracing */ -static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t d= ev, - struct block_device *bdev, - struct blk_user_trace_setup *buts) +static struct blk_trace *blk_trace_setup_prepare(struct request_queue *q, + char *name, dev_t dev, + u32 buf_size, u32 buf_nr, + struct block_device *bdev) { struct blk_trace *bt =3D NULL; struct dentry *dir =3D NULL; @@ -528,31 +529,19 @@ static int do_blk_trace_setup(struct request_queue *q= , char *name, dev_t dev, =20 lockdep_assert_held(&q->debugfs_mutex); =20 - if (!buts->buf_size || !buts->buf_nr) - return -EINVAL; - - strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE); - - /* - * some device names have larger paths - convert the slashes - * to underscores for this to work as expected - */ - strreplace(buts->name, '/', '_'); - /* * bdev can be NULL, as with scsi-generic, this is a helpful as * we can be. */ if (rcu_dereference_protected(q->blk_trace, lockdep_is_held(&q->debugfs_mutex))) { - pr_warn("Concurrent blktraces are not allowed on %s\n", - buts->name); - return -EBUSY; + pr_warn("Concurrent blktraces are not allowed on %s\n", name); + return ERR_PTR(-EBUSY); } =20 bt =3D kzalloc(sizeof(*bt), GFP_KERNEL); if (!bt) - return -ENOMEM; + return ERR_PTR(-ENOMEM); =20 ret =3D -ENOMEM; bt->sequence =3D alloc_percpu(unsigned long); @@ -572,7 +561,7 @@ static int do_blk_trace_setup(struct request_queue *q, = char *name, dev_t dev, if (bdev && !bdev_is_partition(bdev)) dir =3D q->debugfs_dir; else - bt->dir =3D dir =3D debugfs_create_dir(buts->name, blk_debugfs_root); + bt->dir =3D dir =3D debugfs_create_dir(name, blk_debugfs_root); =20 /* * As blktrace relies on debugfs for its interface the debugfs directory @@ -580,8 +569,7 @@ static int do_blk_trace_setup(struct request_queue *q, = char *name, dev_t dev, * files or directories. */ if (IS_ERR_OR_NULL(dir)) { - pr_warn("debugfs_dir not present for %s so skipping\n", - buts->name); + pr_warn("debugfs_dir not present for %s so skipping\n", name); ret =3D -ENOENT; goto err; } @@ -593,17 +581,39 @@ static int do_blk_trace_setup(struct request_queue *q= , char *name, dev_t dev, debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); =20 - bt->rchan =3D relay_open("trace", dir, buts->buf_size, - buts->buf_nr, &blk_relay_callbacks, bt); + bt->rchan =3D relay_open("trace", dir, buf_size, buf_nr, + &blk_relay_callbacks, bt); if (!bt->rchan) goto err; =20 + blk_trace_setup_lba(bt, bdev); + + return bt; + +err: + if (ret) + blk_trace_free(q, bt); + + return ERR_PTR(ret); +} + +static void blk_trace_setup_finalize(struct request_queue *q, + char *name, struct blk_trace *bt, + struct blk_user_trace_setup *buts) + +{ + strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE); + + /* + * some device names have larger paths - convert the slashes + * to underscores for this to work as expected + */ + strreplace(buts->name, '/', '_'); + bt->act_mask =3D buts->act_mask; if (!bt->act_mask) bt->act_mask =3D (u16) -1; =20 - blk_trace_setup_lba(bt, bdev); - /* overwrite with user settings */ if (buts->start_lba) bt->start_lba =3D buts->start_lba; @@ -615,12 +625,6 @@ static int do_blk_trace_setup(struct request_queue *q,= char *name, dev_t dev, =20 rcu_assign_pointer(q->blk_trace, bt); get_probe_ref(); - - ret =3D 0; -err: - if (ret) - blk_trace_free(q, bt); - return ret; } =20 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, @@ -628,17 +632,25 @@ int blk_trace_setup(struct request_queue *q, char *na= me, dev_t dev, char __user *arg) { struct blk_user_trace_setup buts; + struct blk_trace *bt; int ret; =20 ret =3D copy_from_user(&buts, arg, sizeof(buts)); if (ret) return -EFAULT; =20 + if (!buts.buf_size || !buts.buf_nr) + return -EINVAL; + mutex_lock(&q->debugfs_mutex); - ret =3D do_blk_trace_setup(q, name, dev, bdev, &buts); + bt =3D blk_trace_setup_prepare(q, name, dev, buts.buf_size, buts.buf_nr, + bdev); + if (IS_ERR(bt)) { + mutex_unlock(&q->debugfs_mutex); + return PTR_ERR(bt); + } + blk_trace_setup_finalize(q, name, bt, &buts); mutex_unlock(&q->debugfs_mutex); - if (ret) - return ret; =20 if (copy_to_user(arg, &buts, sizeof(buts))) { blk_trace_remove(q); @@ -655,11 +667,14 @@ static int compat_blk_trace_setup(struct request_queu= e *q, char *name, { struct blk_user_trace_setup buts; struct compat_blk_user_trace_setup cbuts; - int ret; + struct blk_trace *bt; =20 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) return -EFAULT; =20 + if (!cbuts.buf_size || !cbuts.buf_nr) + return -EINVAL; + buts =3D (struct blk_user_trace_setup) { .act_mask =3D cbuts.act_mask, .buf_size =3D cbuts.buf_size, @@ -670,10 +685,14 @@ static int compat_blk_trace_setup(struct request_queu= e *q, char *name, }; =20 mutex_lock(&q->debugfs_mutex); - ret =3D do_blk_trace_setup(q, name, dev, bdev, &buts); + bt =3D blk_trace_setup_prepare(q, name, dev, buts.buf_size, buts.buf_nr, + bdev); + if (IS_ERR(bt)) { + mutex_unlock(&q->debugfs_mutex); + return PTR_ERR(bt); + } + blk_trace_setup_finalize(q, name, bt, &buts); mutex_unlock(&q->debugfs_mutex); - if (ret) - return ret; =20 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { blk_trace_remove(q); --=20 2.51.0