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Mon, 09 May 2022 01:47:15 -0700 (PDT) Received: from [192.168.1.7] ([212.22.223.21]) by smtp.gmail.com with ESMTPSA id x24-20020a0565123f9800b0047255d210f9sm1873536lfa.40.2022.05.09.01.47.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 May 2022 01:47:14 -0700 (PDT) Subject: Re: [PATCH v3 10/21] xen/shbuf: switch xen-front-pgdir-shbuf to use INVALID_GRANT_REF To: Juergen Gross , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Boris Ostrovsky , Stefano Stabellini References: <20220505081640.17425-1-jgross@suse.com> <20220505081640.17425-11-jgross@suse.com> From: Oleksandr Message-ID: Date: Mon, 9 May 2022 11:47:13 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20220505081640.17425-11-jgross@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05.05.22 11:16, Juergen Gross wrote: Hello Juergen > Instead of using a private macro for an invalid grant reference use > the common one. > > Signed-off-by: Juergen Gross > --- > V3: > - terminate grant ref list with 0 (Oleksandr Tyshchenko) Reviewed-by: Oleksandr Tyshchenko > --- > drivers/xen/xen-front-pgdir-shbuf.c | 18 +++++------------- > 1 file changed, 5 insertions(+), 13 deletions(-) > > diff --git a/drivers/xen/xen-front-pgdir-shbuf.c b/drivers/xen/xen-front-pgdir-shbuf.c > index a959dee21134..b6433761d42c 100644 > --- a/drivers/xen/xen-front-pgdir-shbuf.c > +++ b/drivers/xen/xen-front-pgdir-shbuf.c > @@ -21,15 +21,6 @@ > > #include > > -#ifndef GRANT_INVALID_REF > -/* > - * FIXME: usage of grant reference 0 as invalid grant reference: > - * grant reference 0 is valid, but never exposed to a PV driver, > - * because of the fact it is already in use/reserved by the PV console. > - */ > -#define GRANT_INVALID_REF 0 > -#endif > - > /** > * This structure represents the structure of a shared page > * that contains grant references to the pages of the shared > @@ -38,6 +29,7 @@ > */ > struct xen_page_directory { > grant_ref_t gref_dir_next_page; > +#define XEN_GREF_LIST_END 0 > grant_ref_t gref[1]; /* Variable length */ > }; > > @@ -83,7 +75,7 @@ grant_ref_t > xen_front_pgdir_shbuf_get_dir_start(struct xen_front_pgdir_shbuf *buf) > { > if (!buf->grefs) > - return GRANT_INVALID_REF; > + return INVALID_GRANT_REF; > > return buf->grefs[0]; > } > @@ -142,7 +134,7 @@ void xen_front_pgdir_shbuf_free(struct xen_front_pgdir_shbuf *buf) > int i; > > for (i = 0; i < buf->num_grefs; i++) > - if (buf->grefs[i] != GRANT_INVALID_REF) > + if (buf->grefs[i] != INVALID_GRANT_REF) > gnttab_end_foreign_access(buf->grefs[i], 0UL); > } > kfree(buf->grefs); > @@ -355,7 +347,7 @@ static void backend_fill_page_dir(struct xen_front_pgdir_shbuf *buf) > } > /* Last page must say there is no more pages. */ > page_dir = (struct xen_page_directory *)ptr; > - page_dir->gref_dir_next_page = GRANT_INVALID_REF; > + page_dir->gref_dir_next_page = XEN_GREF_LIST_END; > } > > /** > @@ -384,7 +376,7 @@ static void guest_fill_page_dir(struct xen_front_pgdir_shbuf *buf) > > if (grefs_left <= XEN_NUM_GREFS_PER_PAGE) { > to_copy = grefs_left; > - page_dir->gref_dir_next_page = GRANT_INVALID_REF; > + page_dir->gref_dir_next_page = XEN_GREF_LIST_END; > } else { > to_copy = XEN_NUM_GREFS_PER_PAGE; > page_dir->gref_dir_next_page = buf->grefs[i + 1]; -- Regards, Oleksandr Tyshchenko