From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Maier Subject: Re: [patch] mm, mempool: do not allow atomic resizing Date: Wed, 11 Mar 2015 13:41:36 +0100 Message-ID: <55003800.4020503@linux.vnet.ibm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Rientjes , Andrew Morton Cc: Martin Schwidefsky , Heiko Carstens , Steve French , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-s390-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-scsi@vger.kernel.org for the zfcp part: Acked-by: Steffen Maier On 03/08/2015 04:19 AM, David Rientjes wrote: > Allocating a large number of elements in atomic context could quickly > deplete memory reserves, so just disallow atomic resizing entirely. > > Nothing currently uses mempool_resize() with anything other than > GFP_KERNEL, so convert existing callers to drop the gfp_mask. > > Signed-off-by: David Rientjes > --- > drivers/s390/scsi/zfcp_erp.c | 4 ++-- > fs/cifs/connect.c | 6 ++---- > include/linux/mempool.h | 2 +- > mm/mempool.c | 9 +++++---- > 4 files changed, 10 insertions(+), 11 deletions(-) > > diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_er= p.c > --- a/drivers/s390/scsi/zfcp_erp.c > +++ b/drivers/s390/scsi/zfcp_erp.c > @@ -738,11 +738,11 @@ static int zfcp_erp_adapter_strategy_open_fsf(s= truct zfcp_erp_action *act) > return ZFCP_ERP_FAILED; > > if (mempool_resize(act->adapter->pool.sr_data, > - act->adapter->stat_read_buf_num, GFP_KERNEL)) > + act->adapter->stat_read_buf_num)) > return ZFCP_ERP_FAILED; > > if (mempool_resize(act->adapter->pool.status_read_req, > - act->adapter->stat_read_buf_num, GFP_KERNEL)) > + act->adapter->stat_read_buf_num)) > return ZFCP_ERP_FAILED; > > atomic_set(&act->adapter->stat_miss, act->adapter->stat_read_buf_n= um); > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c > --- a/fs/cifs/connect.c > +++ b/fs/cifs/connect.c > @@ -773,8 +773,7 @@ static void clean_demultiplex_info(struct TCP_Ser= ver_Info *server) > > length =3D atomic_dec_return(&tcpSesAllocCount); > if (length > 0) > - mempool_resize(cifs_req_poolp, length + cifs_min_rcv, > - GFP_KERNEL); > + mempool_resize(cifs_req_poolp, length + cifs_min_rcv); > } > > static int > @@ -848,8 +847,7 @@ cifs_demultiplex_thread(void *p) > > length =3D atomic_inc_return(&tcpSesAllocCount); > if (length > 1) > - mempool_resize(cifs_req_poolp, length + cifs_min_rcv, > - GFP_KERNEL); > + mempool_resize(cifs_req_poolp, length + cifs_min_rcv); > > set_freezable(); > while (server->tcpStatus !=3D CifsExiting) { > diff --git a/include/linux/mempool.h b/include/linux/mempool.h > --- a/include/linux/mempool.h > +++ b/include/linux/mempool.h > @@ -29,7 +29,7 @@ extern mempool_t *mempool_create_node(int min_nr, m= empool_alloc_t *alloc_fn, > mempool_free_t *free_fn, void *pool_data, > gfp_t gfp_mask, int nid); > > -extern int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp= _mask); > +extern int mempool_resize(mempool_t *pool, int new_min_nr); > extern void mempool_destroy(mempool_t *pool); > extern void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask); > extern void mempool_free(void *element, mempool_t *pool); > diff --git a/mm/mempool.c b/mm/mempool.c > --- a/mm/mempool.c > +++ b/mm/mempool.c > @@ -113,23 +113,24 @@ EXPORT_SYMBOL(mempool_create_node); > * mempool_create(). > * @new_min_nr: the new minimum number of elements guaranteed to be > * allocated for this pool. > - * @gfp_mask: the usual allocation bitmask. > * > * This function shrinks/grows the pool. In the case of growing, > * it cannot be guaranteed that the pool will be grown to the new > * size immediately, but new mempool_free() calls will refill it. > + * This function may sleep. > * > * Note, the caller must guarantee that no mempool_destroy is calle= d > * while this function is running. mempool_alloc() & mempool_free() > * might be called (eg. from IRQ contexts) while this function exec= utes. > */ > -int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask) > +int mempool_resize(mempool_t *pool, int new_min_nr) > { > void *element; > void **new_elements; > unsigned long flags; > > BUG_ON(new_min_nr <=3D 0); > + might_sleep(); > > spin_lock_irqsave(&pool->lock, flags); > if (new_min_nr <=3D pool->min_nr) { > @@ -145,7 +146,7 @@ int mempool_resize(mempool_t *pool, int new_min_n= r, gfp_t gfp_mask) > spin_unlock_irqrestore(&pool->lock, flags); > > /* Grow the pool */ > - new_elements =3D kmalloc(new_min_nr * sizeof(*new_elements), gfp_ma= sk); > + new_elements =3D kmalloc(new_min_nr * sizeof(*new_elements), GFP_KE= RNEL); > if (!new_elements) > return -ENOMEM; > > @@ -164,7 +165,7 @@ int mempool_resize(mempool_t *pool, int new_min_n= r, gfp_t gfp_mask) > > while (pool->curr_nr < pool->min_nr) { > spin_unlock_irqrestore(&pool->lock, flags); > - element =3D pool->alloc(gfp_mask, pool->pool_data); > + element =3D pool->alloc(GFP_KERNEL, pool->pool_data); > if (!element) > goto out; > spin_lock_irqsave(&pool->lock, flags); > --=20 Mit freundlichen Gr=FC=DFen / Kind regards Steffen Maier Linux on System z Development IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294