From 8ef8d195430ca3542d0434cf25e5115484b9fa32 Mon Sep 17 00:00:00 2001 From: Christian Lamparter Date: Wed, 4 Oct 2017 01:00:09 +0200 Subject: [PATCH 17/25] crypto: crypto4xx - add backlog queue support Previously, If the crypto4xx driver used all available security contexts, it would simply refuse new requests with -EAGAIN. CRYPTO_TFM_REQ_MAY_BACKLOG was ignored. in case of dm-crypt.c's crypt_convert() function this was causing the following errors to manifest, if the system was pushed hard enough: | EXT4-fs warning (dm-1): ext4_end_bio:314: I/O error -5 writing to ino .. | EXT4-fs warning (dm-1): ext4_end_bio:314: I/O error -5 writing to ino .. | EXT4-fs warning (dm-1): ext4_end_bio:314: I/O error -5 writing to ino .. | JBD2: Detected IO errors while flushing file data on dm-1-8 | Aborting journal on device dm-1-8. | EXT4-fs error : ext4_journal_check_start:56: Detected aborted journal | EXT4-fs (dm-1): Remounting filesystem read-only | EXT4-fs : ext4_writepages: jbd2_start: 2048 pages, inode 498...; err -30 (This did cause corruptions due to failed writes) To fix this mess, the crypto4xx driver needs to notifiy the user to slow down. This can be achieved by returning -EBUSY on requests, once the crypto hardware was falling behind. Note: -EBUSY has two different meanings. Setting the flag CRYPTO_TFM_REQ_MAY_BACKLOG implies that the request was successfully queued, by the crypto driver. To achieve this requirement, the implementation introduces a threshold check and adds logic to the completion routines in much the same way as AMD's Cryptographic Coprocessor (CCP) driver do. Note2: Tests showed that dm-crypt starved ipsec traffic. Under load, ipsec links dropped to 0 Kbits/s. This is because dm-crypt's callback would instantly queue the next request. In order to not starve ipsec, the driver reserves a small portion of the available crypto contexts for this purpose. Signed-off-by: Christian Lamparter Signed-off-by: Herbert Xu --- drivers/crypto/amcc/crypto4xx_core.c | 47 ++++++++++++++++++++++++++++++------ drivers/crypto/amcc/crypto4xx_core.h | 3 ++- 2 files changed, 41 insertions(+), 9 deletions(-) --- a/drivers/crypto/amcc/crypto4xx_core.c +++ b/drivers/crypto/amcc/crypto4xx_core.c @@ -39,6 +39,7 @@ #include #include #include +#include #include "crypto4xx_reg_def.h" #include "crypto4xx_core.h" #include "crypto4xx_sa.h" @@ -578,8 +579,10 @@ static u32 crypto4xx_ablkcipher_done(str } crypto4xx_ret_sg_desc(dev, pd_uinfo); - if (ablk_req->base.complete != NULL) - ablk_req->base.complete(&ablk_req->base, 0); + + if (pd_uinfo->state & PD_ENTRY_BUSY) + ablkcipher_request_complete(ablk_req, -EINPROGRESS); + ablkcipher_request_complete(ablk_req, 0); return 0; } @@ -596,9 +599,10 @@ static u32 crypto4xx_ahash_done(struct c crypto4xx_copy_digest_to_dst(pd_uinfo, crypto_tfm_ctx(ahash_req->base.tfm)); crypto4xx_ret_sg_desc(dev, pd_uinfo); - /* call user provided callback function x */ - if (ahash_req->base.complete != NULL) - ahash_req->base.complete(&ahash_req->base, 0); + + if (pd_uinfo->state & PD_ENTRY_BUSY) + ahash_request_complete(ahash_req, -EINPROGRESS); + ahash_request_complete(ahash_req, 0); return 0; } @@ -709,6 +713,7 @@ u32 crypto4xx_build_pd(struct crypto_asy struct pd_uinfo *pd_uinfo = NULL; unsigned int nbytes = datalen, idx; u32 gd_idx = 0; + bool is_busy; /* figure how many gd is needed */ num_gd = sg_nents_for_len(src, datalen); @@ -739,6 +744,31 @@ u32 crypto4xx_build_pd(struct crypto_asy * already got must be return the original place. */ spin_lock_irqsave(&dev->core_dev->lock, flags); + /* + * Let the caller know to slow down, once more than 13/16ths = 81% + * of the available data contexts are being used simultaneously. + * + * With PPC4XX_NUM_PD = 256, this will leave a "backlog queue" for + * 31 more contexts. Before new requests have to be rejected. + */ + if (req->flags & CRYPTO_TFM_REQ_MAY_BACKLOG) { + is_busy = ((dev->pdr_head - dev->pdr_tail) % PPC4XX_NUM_PD) >= + ((PPC4XX_NUM_PD * 13) / 16); + } else { + /* + * To fix contention issues between ipsec (no blacklog) and + * dm-crypto (backlog) reserve 32 entries for "no backlog" + * data contexts. + */ + is_busy = ((dev->pdr_head - dev->pdr_tail) % PPC4XX_NUM_PD) >= + ((PPC4XX_NUM_PD * 15) / 16); + + if (is_busy) { + spin_unlock_irqrestore(&dev->core_dev->lock, flags); + return -EBUSY; + } + } + if (num_gd) { fst_gd = crypto4xx_get_n_gd(dev, num_gd); if (fst_gd == ERING_WAS_FULL) { @@ -893,11 +923,12 @@ u32 crypto4xx_build_pd(struct crypto_asy sa->sa_command_1.bf.hash_crypto_offset = 0; pd->pd_ctl.w = ctx->pd_ctl; pd->pd_ctl_len.w = 0x00400000 | datalen; - pd_uinfo->state = PD_ENTRY_INUSE; + pd_uinfo->state = PD_ENTRY_INUSE | (is_busy ? PD_ENTRY_BUSY : 0); + wmb(); /* write any value to push engine to read a pd */ writel(1, dev->ce_base + CRYPTO4XX_INT_DESCR_RD); - return -EINPROGRESS; + return is_busy ? -EBUSY : -EINPROGRESS; } /** @@ -1002,7 +1033,7 @@ static void crypto4xx_bh_tasklet_cb(unsi tail = core_dev->dev->pdr_tail; pd_uinfo = &core_dev->dev->pdr_uinfo[tail]; pd = &core_dev->dev->pdr[tail]; - if ((pd_uinfo->state == PD_ENTRY_INUSE) && + if ((pd_uinfo->state & PD_ENTRY_INUSE) && pd->pd_ctl.bf.pe_done && !pd->pd_ctl.bf.host_ready) { pd->pd_ctl.bf.pe_done = 0; --- a/drivers/crypto/amcc/crypto4xx_core.h +++ b/drivers/crypto/amcc/crypto4xx_core.h @@ -44,7 +44,8 @@ #define PPC4XX_LAST_SD (PPC4XX_NUM_SD - 1) #define PPC4XX_SD_BUFFER_SIZE 2048 -#define PD_ENTRY_INUSE 1 +#define PD_ENTRY_BUSY BIT(1) +#define PD_ENTRY_INUSE BIT(0) #define PD_ENTRY_FREE 0 #define ERING_WAS_FULL 0xffffffff