From 211e5b7a0007e6a172eafdb89c512768f82d73bf Mon Sep 17 00:00:00 2001 From: Karsten Graul Date: Sun, 26 Jul 2020 20:34:27 +0200 Subject: [PATCH 1/2] s390/ism: indicate correct error reason in ism_alloc_dmb() When the ism driver allocates a new dmb in ism_alloc_dmb() it must first check for and reserve a slot in the sba bitmap. When find_next_zero_bit() finds no free slot then the return code is -ENOMEM. This code conflicts with the error when the alloc() fails later in the code. As a result of that the caller can not differentiate between out-of-memory conditions and sba-bitmap-full conditions. Fix that by using the return code -ENOSPC when the sba slot reservation failed. Reviewed-by: Ursula Braun Signed-off-by: Karsten Graul Signed-off-by: David S. Miller --- drivers/s390/net/ism_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c index c7fade836d83..5fbe9eae84d1 100644 --- a/drivers/s390/net/ism_drv.c +++ b/drivers/s390/net/ism_drv.c @@ -231,7 +231,7 @@ static int ism_alloc_dmb(struct ism_dev *ism, struct smcd_dmb *dmb) bit = find_next_zero_bit(ism->sba_bitmap, ISM_NR_DMBS, ISM_DMB_BIT_OFFSET); if (bit == ISM_NR_DMBS) - return -ENOMEM; + return -ENOSPC; dmb->sba_idx = bit; } From 72b7f6c48708e4524765a2f1316063207d8e0cd5 Mon Sep 17 00:00:00 2001 From: Karsten Graul Date: Sun, 26 Jul 2020 20:34:28 +0200 Subject: [PATCH 2/2] net/smc: unique reason code for exceeded max dmb count When the maximum dmb buffer limit for an ism device is reached no more dmb buffers can be registered. When this happens the reason code is set to SMC_CLC_DECL_MEM indicating out-of-memory. This is the same reason code that is used when no memory could be allocated for the new dmb buffer. This is confusing for users when they see this error but there is more memory available. To solve this set a separate new reason code when the maximum dmb limit exceeded. Reviewed-by: Ursula Braun Signed-off-by: Karsten Graul Signed-off-by: David S. Miller --- net/smc/af_smc.c | 13 +++++++++---- net/smc/smc_clc.h | 1 + net/smc/smc_core.c | 4 ++-- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 832e36269b10..e7649bbc2b87 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -719,8 +719,11 @@ static int smc_connect_ism(struct smc_sock *smc, } /* Create send and receive buffers */ - if (smc_buf_create(smc, true)) - return smc_connect_abort(smc, SMC_CLC_DECL_MEM, + rc = smc_buf_create(smc, true); + if (rc) + return smc_connect_abort(smc, (rc == -ENOSPC) ? + SMC_CLC_DECL_MAX_DMB : + SMC_CLC_DECL_MEM, ini->cln_first_contact); smc_conn_save_peer_info(smc, aclc); @@ -1200,12 +1203,14 @@ static int smc_listen_ism_init(struct smc_sock *new_smc, } /* Create send and receive buffers */ - if (smc_buf_create(new_smc, true)) { + rc = smc_buf_create(new_smc, true); + if (rc) { if (ini->cln_first_contact == SMC_FIRST_CONTACT) smc_lgr_cleanup_early(&new_smc->conn); else smc_conn_free(&new_smc->conn); - return SMC_CLC_DECL_MEM; + return (rc == -ENOSPC) ? SMC_CLC_DECL_MAX_DMB : + SMC_CLC_DECL_MEM; } return 0; diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h index 76c2b150d040..cf7b45306f4e 100644 --- a/net/smc/smc_clc.h +++ b/net/smc/smc_clc.h @@ -48,6 +48,7 @@ #define SMC_CLC_DECL_NOACTLINK 0x030a0000 /* no active smc-r link in lgr */ #define SMC_CLC_DECL_NOSRVLINK 0x030b0000 /* SMC-R link from srv not found */ #define SMC_CLC_DECL_VERSMISMAT 0x030c0000 /* SMC version mismatch */ +#define SMC_CLC_DECL_MAX_DMB 0x030d0000 /* SMC-D DMB limit exceeded */ #define SMC_CLC_DECL_SYNCERR 0x04000000 /* synchronization error */ #define SMC_CLC_DECL_PEERDECL 0x05000000 /* peer declined during handshake */ #define SMC_CLC_DECL_INTERR 0x09990000 /* internal error */ diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index f82a2e599917..b42fa3b00d00 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1614,7 +1614,7 @@ static struct smc_buf_desc *smcd_new_buf_create(struct smc_link_group *lgr, rc = smc_ism_register_dmb(lgr, bufsize, buf_desc); if (rc) { kfree(buf_desc); - return ERR_PTR(-EAGAIN); + return (rc == -ENOMEM) ? ERR_PTR(-EAGAIN) : ERR_PTR(rc); } buf_desc->pages = virt_to_page(buf_desc->cpu_addr); /* CDC header stored in buf. So, pretend it was smaller */ @@ -1688,7 +1688,7 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb) } if (IS_ERR(buf_desc)) - return -ENOMEM; + return PTR_ERR(buf_desc); if (!is_smcd) { if (smcr_buf_map_usable_links(lgr, buf_desc, is_rmb)) {