Re: [PATCH v2] bsg: use pr_debug instead of hand craftet macros

From: Joe Perches
Date: Tue Jan 23 2018 - 07:46:01 EST


On Tue, 2018-01-23 at 11:55 +0100, Johannes Thumshirn wrote:
> Use pr_debug instead of hand craftet macros. This way it is not needed to
> re-compile the kernel to enable bsg debug outputs and it's possible to
> selectively enable specific prints.

Perhaps the email subject could be improved to describe
the new macro and as well, this macro, without a pr_fmt
define somewhat above it loses the __func__ output too.

Perhaps add a description of the capability of the
dynamic debug facility to add the function name using +f.

> Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> Cc: Joe Perches <joe@xxxxxxxxxxx>
> Cc: Bart Van Assche <Bart.VanAssche@xxxxxxx>
>
> ---
> Changes to v1:
> * Aligned arguments (Bart)
> * Include bd->name in macro (Joe)
> ---
> block/bsg.c | 40 +++++++++++++++++-----------------------
> 1 file changed, 17 insertions(+), 23 deletions(-)
>
> diff --git a/block/bsg.c b/block/bsg.c
> index 452f94f1c5d4..a1bcbb6ba50b 100644
> --- a/block/bsg.c
> +++ b/block/bsg.c
> @@ -32,6 +32,9 @@
> #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
> #define BSG_VERSION "0.4"
>
> +#define bsg_dbg(bd, fmt, ...) \
> + pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
> +
> struct bsg_device {
> struct request_queue *queue;
> spinlock_t lock;
> @@ -55,14 +58,6 @@ enum {
> #define BSG_DEFAULT_CMDS 64
> #define BSG_MAX_DEVS 32768
>
> -#undef BSG_DEBUG
> -
> -#ifdef BSG_DEBUG
> -#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args)
> -#else
> -#define dprintk(fmt, args...)
> -#endif
> -
> static DEFINE_MUTEX(bsg_mutex);
> static DEFINE_IDR(bsg_minor_idr);
>
> @@ -123,7 +118,7 @@ static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
>
> bc->bd = bd;
> INIT_LIST_HEAD(&bc->list);
> - dprintk("%s: returning free cmd %p\n", bd->name, bc);
> + bsg_dbg(bd, "returning free cmd %p\n", bc);
> return bc;
> out:
> spin_unlock_irq(&bd->lock);
> @@ -222,7 +217,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t mode)
> if (!bcd->class_dev)
> return ERR_PTR(-ENXIO);
>
> - dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
> + bsg_dbg(bd, "map hdr %llx/%u %llx/%u\n",
> + (unsigned long long) hdr->dout_xferp,
> hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
> hdr->din_xfer_len);
>
> @@ -299,8 +295,8 @@ static void bsg_rq_end_io(struct request *rq, blk_status_t status)
> struct bsg_device *bd = bc->bd;
> unsigned long flags;
>
> - dprintk("%s: finished rq %p bc %p, bio %p\n",
> - bd->name, rq, bc, bc->bio);
> + bsg_dbg(bd, "finished rq %p bc %p, bio %p\n",
> + rq, bc, bc->bio);
>
> bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
>
> @@ -333,7 +329,7 @@ static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
> list_add_tail(&bc->list, &bd->busy_list);
> spin_unlock_irq(&bd->lock);
>
> - dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
> + bsg_dbg(bd, "queueing rq %p, bc %p\n", rq, bc);
>
> rq->end_io_data = bc;
> blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io);
> @@ -379,7 +375,7 @@ static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
> }
> } while (1);
>
> - dprintk("%s: returning done %p\n", bd->name, bc);
> + bsg_dbg(bd, "returning done %p\n", bc);
>
> return bc;
> }
> @@ -390,7 +386,7 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
> struct scsi_request *req = scsi_req(rq);
> int ret = 0;
>
> - dprintk("rq %p bio %p 0x%x\n", rq, bio, req->result);
> + pr_debug("rq %p bio %p 0x%x\n", rq, bio, req->result);
> /*
> * fill in all the output members
> */
> @@ -469,7 +465,7 @@ static int bsg_complete_all_commands(struct bsg_device *bd)
> struct bsg_command *bc;
> int ret, tret;
>
> - dprintk("%s: entered\n", bd->name);
> + bsg_dbg(bd, "entered\n");
>
> /*
> * wait for all commands to complete
> @@ -572,7 +568,7 @@ bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> int ret;
> ssize_t bytes_read;
>
> - dprintk("%s: read %zd bytes\n", bd->name, count);
> + bsg_dbg(bd, "read %zd bytes\n", count);
>
> bsg_set_block(bd, file);
>
> @@ -646,7 +642,7 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
> ssize_t bytes_written;
> int ret;
>
> - dprintk("%s: write %zd bytes\n", bd->name, count);
> + bsg_dbg(bd, "write %zd bytes\n", count);
>
> if (unlikely(uaccess_kernel()))
> return -EINVAL;
> @@ -664,7 +660,7 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
> if (!bytes_written || err_block_err(ret))
> bytes_written = ret;
>
> - dprintk("%s: returning %zd\n", bd->name, bytes_written);
> + bsg_dbg(bd, "returning %zd\n", bytes_written);
> return bytes_written;
> }
>
> @@ -717,7 +713,7 @@ static int bsg_put_device(struct bsg_device *bd)
> hlist_del(&bd->dev_list);
> mutex_unlock(&bsg_mutex);
>
> - dprintk("%s: tearing down\n", bd->name);
> + bsg_dbg(bd, "tearing down\n");
>
> /*
> * close can always block
> @@ -744,9 +740,7 @@ static struct bsg_device *bsg_add_device(struct inode *inode,
> struct file *file)
> {
> struct bsg_device *bd;
> -#ifdef BSG_DEBUG
> unsigned char buf[32];
> -#endif
>
> if (!blk_queue_scsi_passthrough(rq)) {
> WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
> @@ -771,7 +765,7 @@ static struct bsg_device *bsg_add_device(struct inode *inode,
> hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
>
> strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
> - dprintk("bound to <%s>, max queue %d\n",
> + bsg_dbg(bd, "bound to <%s>, max queue %d\n",
> format_dev_t(buf, inode->i_rdev), bd->max_queue);
>
> mutex_unlock(&bsg_mutex);