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Message-ID: <41548132-246a-f6d0-473d-e2ab72a86e15@st.com>
Date: Thu, 8 Sep 2016 11:54:27 +0200
From: loic pallardy <loic.pallardy@...com>
To: Lee Jones <lee.jones@...aro.org>
CC: <bjorn.andersson@...aro.org>, <ohad@...ery.com>,
<linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<kernel@...inux.com>
Subject: Re: [PATCH v2 13/19] remoteproc: core: Append resource only if spare
resource present
On 09/08/2016 11:33 AM, Lee Jones wrote:
> On Wed, 31 Aug 2016, Loic Pallardy wrote:
>
>> This patch renames rproc_add_resource_table_entry in __add_rsc_tbl_entry
>> to have shorter function name and adds spare resource support.
>> To guarantee remoteproc won't overwrite firmware data when copying
>> back modified resource table, __add_rsc_tbl_entry verifies first that
>> resource table owns a spare resource and uses spare bytes to create
>> a new resource entry. Spare resource is updated according to changes.
>>
>> Signed-off-by: Loic Pallardy <loic.pallardy@...com>
>> ---
>> drivers/remoteproc/remoteproc_core.c | 54 ++++++++++++++++++++----------------
>> 1 file changed, 30 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>> index aff1a00..25a429b 100644
>> --- a/drivers/remoteproc/remoteproc_core.c
>> +++ b/drivers/remoteproc/remoteproc_core.c
>> @@ -1107,39 +1107,34 @@ static int __update_rsc_tbl_entry(struct rproc *rproc,
>> return !updated;
>> }
>>
>> -static struct resource_table*
>> -rproc_add_resource_table_entry(struct rproc *rproc,
>> +static int __add_rsc_tbl_entry(struct rproc *rproc,
>
> Once again, I prefer plain English over cryptic abbreviations. Makes
> things much more difficult for developers who are new to, or are just
> dipping into RemoteProc code.
OK
>
>> struct rproc_request_resource *request,
>> - struct resource_table *old_table, int *tablesz)
>> + struct resource_table *table, int tablesz)
>> {
>> - struct resource_table *table;
>> struct fw_rsc_hdr h;
>> + struct fw_rsc_spare spare;
>> void *new_rsc_loc;
>> void *fw_header_loc;
>> void *start_of_rscs;
>> int new_rsc_offset;
>> - int size = *tablesz;
>> - int i;
>> + int new_spare_offset;
>> + int i, spare_index = 0;
>>
>> h.type = request->type;
>>
>> - new_rsc_offset = size;
>> + /* check available spare size */
>
> In keeping with the existing comments, please use correct grammar.
>
> Capital letters to start and for names etc.
>
> Much more professional IMO.
I'll correct
>
>> + spare.len = __get_rsc_tbl_spare_size(rproc, table, tablesz, &spare_index);
>> + if (spare.len < (sizeof(h) + request->size + 4)) /* new offset entry */
>
> Not sure that comment makes the code any clearer?
>
> All you're doing here is checking if we have enough space, right?
>
> I think the 4 is a 'magic' number. I'd either provide a comment (like
> I did below), or define it.
I'll add a comment as you did to explain the "4".
>
>> + return -EPERM;
>
> What does this have to do with permissions?
Yes sure, I'll replaced by -EINVAL as resource too large compare to
spare area capability.
>
>> - /*
>> - * Allocate another contiguous chunk of memory, large enough to
>> - * contain the new, expanded resource table.
>> - *
>> - * The +4 is for the extra offset[] element in the top level header
>> - */
>> - size += sizeof(struct fw_rsc_hdr) + request->size + 4;
>> - table = devm_kmemdup(&rproc->dev, old_table, size, GFP_KERNEL);
>> - if (!table)
>> - return ERR_PTR(-ENOMEM);
>> + new_rsc_offset = table->offset[spare_index];
>>
>> /* Shunt table by 4 Bytes to account for the extra offset[] element */
>> start_of_rscs = (void *)table + table->offset[0];
>> memmove(start_of_rscs + 4,
>> start_of_rscs, new_rsc_offset - table->offset[0]);
>> +
>> + spare.len -= 4;
>
> This probably deserves a comment too.
I'll add a comment too
>
> /*
> * The spare area is finite. Since we are increasing the size of the
> * header and shunting the tables, we need to reduce the size of the
> * available 'spare' area by the shunt size.
> */
>
>> new_rsc_offset += 4;
>>
>> /* Update existing resource entry's offsets */
>> @@ -1153,13 +1148,27 @@ rproc_add_resource_table_entry(struct rproc *rproc,
>> /* Copy new firmware header into table */
>> fw_header_loc = (void *)table + new_rsc_offset;
>> memcpy(fw_header_loc, &h, sizeof(h));
>> + spare.len -= sizeof(h);
>>
>> /* Copy new resource entry into table */
>> new_rsc_loc = (void *)fw_header_loc + sizeof(h);
>> memcpy(new_rsc_loc, request->resource, request->size);
>> + spare.len -= request->size;
>>
>> - *tablesz = size;
>> - return table;
>> + /* create new rsc spare resource at the end of remaining spare */
>
> Same comment about using nice grammar in comments.
Ok
Thanks,
Loic
>
>> + new_spare_offset = new_rsc_offset + sizeof(h) + request->size;
>> + h.type = RSC_SPARE;
>> +
>> + fw_header_loc = (void *)table + new_spare_offset;
>> + memcpy(fw_header_loc, &h, sizeof(h));
>> +
>> + new_rsc_loc = (void *)fw_header_loc + sizeof(h);
>> + memcpy(new_rsc_loc, &spare, sizeof(spare));
>> +
>> + /* update spare offset */
>> + table->offset[spare_index] = new_spare_offset;
>> +
>> + return 0;
>> }
>>
>> static struct resource_table*
>> @@ -1203,12 +1212,9 @@ rproc_apply_resource_overrides(struct rproc *rproc,
>> continue;
>>
>> /* Didn't find matching resource entry -- creating a new one. */
>> - table = rproc_add_resource_table_entry(rproc, resource,
>> - table, &size);
>> - if (IS_ERR(table))
>> + updated = __add_rsc_tbl_entry(rproc, resource, table, size);
>> + if (updated)
>> goto out;
>> -
>> - *orig_table = table;
>> }
>>
>> rproc_dump_resource_table(rproc, table, size);
>
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