On Monday 19 June 2006 14:24, Ian Dowse wrote:
> In message <[EMAIL PROTECTED]>, John Baldwin writes:
> >On Friday 16 June 2006 20:47, Ian Dowse wrote:
> >> - driver calls firmware_get, firmware image loaded and fp->file set to
non-NULL
> >> - manually kldload some_module_that_depends_on_firmware_image
> >> - driver calls firmware_put, unloadentry called and sets fp->file = NULL
> >
> >In practice no modules depend on firmware modules. :) I think we should
> >take the approach of not clearing fp->file in unloadentry() however.
> >That would result in correct behavior in every case I can think of (or as
> >close to correct as you can get). In the above case the
> >linker_file_unload() would have fail leaving the firmware module around.
>
> How about the following patch? In the above case linker_file_unload()
> would actually succeed because the linker file reference count is
> just dropping from 2 to 1, so we'd get a negative reference count
> later if we kept fp->file non-NULL after it returns.
>
> Ian
>
> Index: subr_firmware.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/kern/subr_firmware.c,v
> retrieving revision 1.2
> diff -u -r1.2 subr_firmware.c
> --- subr_firmware.c 10 Jun 2006 17:04:07 -0000 1.2
> +++ subr_firmware.c 19 Jun 2006 18:15:21 -0000
> @@ -206,7 +206,7 @@
> {
> struct firmware *fp;
> linker_file_t file;
> - int i;
> + int i, err;
>
> mtx_lock(&firmware_mtx);
> for (;;) {
> @@ -226,9 +226,18 @@
> fp->file = NULL;
> mtx_unlock(&firmware_mtx);
>
> - linker_file_unload(file, LINKER_UNLOAD_NORMAL);
> -
> + err = linker_file_unload(file, LINKER_UNLOAD_NORMAL);
> mtx_lock(&firmware_mtx);
> + if (err) {
> + /*
> + * If linker_file_unload() failed then we still hold
> + * a reference on the module so it should not be
> + * possible for it to go away or be re-registered.
> + */
> + KASSERT(fp->file == NULL,
> + ("firmware entry reused while referenced!"));
> + fp->file = file;
> + }
> }
> mtx_unlock(&firmware_mtx);
> }
>
Ok.
--
John Baldwin
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