From: jim.cromie@gmail.com
To: Alexandru Goia <goia.i.alexandru@gmail.com>
Cc: kernelnewbies@kernelnewbies.org
Subject: Re: Linux 4 block device driver infrastructure
Date: Thu, 7 Dec 2023 18:25:48 -0700 [thread overview]
Message-ID: <CAJfuBxxQwOCcDyJPx6encbNn21pRGKk036oM5fWzgckRi8+COA@mail.gmail.com> (raw)
In-Reply-To: <CADmgqahZXAWJiQXWXWGg6u=EFW0UCrWpcMBJdFt2D_rDL2YQkA@mail.gmail.com>
On Thu, Nov 30, 2023 at 9:08 AM Alexandru Goia
<goia.i.alexandru@gmail.com> wrote:
>
> Greetings !
>
> I am a Unix/Linux hobbyist from Romania, interested in kernel stuff.
> I need some clarifications, related to block device subsystem in Linux 4,
> so I will ask them here, if you can answer me, please...
>
> 1) Why (in Linux 4) in struct block_device_operations, the (*open)(struct block_device *, fmode_t)
> has a different signature than the (*release)(struct gendisk *, fmode_t) ? Why open()
> uses block_device, while release() uses gendisk ? They are both in a struct
> block_device_operations. Why they not refer to the same thing ?
>
in linux current, its not like that:
struct block_device_operations {
void (*submit_bio)(struct bio *bio);
int (*poll_bio)(struct bio *bio, struct io_comp_batch *iob,
unsigned int flags);
int (*open)(struct gendisk *disk, blk_mode_t mode);
void (*release)(struct gendisk *disk);
Old books are still useful, but new code is a much better place to look.
> I understand that gendisk refer to a real disk, and block_device (s) to logical disk (s)
> and partitions. But why the kernel developers have chosen to use different signatures ?
>
> 2) Release() is also synonim to close() ?
> 3) Why is not explicitely present a close() function ?
> 4) Why struct gendisk does not have inside it pointers to struct block_device ?
>
> Thank you very much,
> Alexander,
> Computer hobbyist,
> Romania
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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prev parent reply other threads:[~2023-12-08 1:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 16:06 Linux 4 block device driver infrastructure Alexandru Goia
2023-11-30 16:41 ` Fwd: " Alexandru Goia
2023-12-08 1:25 ` jim.cromie [this message]
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