* [PATCH 1/3] staging: r8188eu: convert type of second parameter of rtw_*_encrypt()
2021-08-29 11:25 [PATCH 0/3] staging: r8188eu: clean up unnecessary type casts Michael Straube
@ 2021-08-29 11:25 ` Michael Straube
2021-08-29 11:25 ` [PATCH 2/3] staging: r8188eu: convert type of second parameter of rtw_*_decrypt() Michael Straube
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Michael Straube @ 2021-08-29 11:25 UTC (permalink / raw)
To: gregkh
Cc: Larry.Finger, phil, martin, fmdefrancesco, linux-staging,
linux-kernel, Michael Straube
Convert the type of the second parameter of the rtw_*_encrypt() functions
to struct xmit_frame.
All callers of the functions cast the type to (u8 *) and in the functions
it is casted back to the original type. Changing the type of the second
parameter to struct xmit_frame avoids these unnecessary casts and improves
readability.
Signed-off-by: Michael Straube <straube.linux@gmail.com>
---
drivers/staging/r8188eu/core/rtw_mlme_ext.c | 2 +-
drivers/staging/r8188eu/core/rtw_security.c | 36 +++++++++----------
drivers/staging/r8188eu/core/rtw_xmit.c | 6 ++--
.../staging/r8188eu/include/rtw_security.h | 6 ++--
4 files changed, 23 insertions(+), 27 deletions(-)
diff --git a/drivers/staging/r8188eu/core/rtw_mlme_ext.c b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
index 5a472a4954b0..d78d1b00f66c 100644
--- a/drivers/staging/r8188eu/core/rtw_mlme_ext.c
+++ b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
@@ -5049,7 +5049,7 @@ void issue_auth(struct adapter *padapter, struct sta_info *psta, unsigned short
pattrib->last_txcmdsz = pattrib->pktlen;
- rtw_wep_encrypt(padapter, (u8 *)pmgntframe);
+ rtw_wep_encrypt(padapter, pmgntframe);
DBG_88E("%s\n", __func__);
dump_mgntframe(padapter, pmgntframe);
}
diff --git a/drivers/staging/r8188eu/core/rtw_security.c b/drivers/staging/r8188eu/core/rtw_security.c
index 5aa893ab46e9..5168159d8ae7 100644
--- a/drivers/staging/r8188eu/core/rtw_security.c
+++ b/drivers/staging/r8188eu/core/rtw_security.c
@@ -77,7 +77,7 @@ static void arcfour_encrypt(struct arc4context *parc4ctx, u8 *dest, u8 *src, u32
/*
Need to consider the fragment situation
*/
-void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
+void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
{ /* exclude ICV */
union {
__le32 f0;
@@ -91,17 +91,15 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
u8 *pframe, *payload, *iv; /* wepkey */
u8 wepkey[16];
u8 hw_hdr_offset = 0;
- struct pkt_attrib *pattrib = &((struct xmit_frame *)pxmitframe)->attrib;
+ struct pkt_attrib *pattrib = &pxmitframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
- if (!((struct xmit_frame *)pxmitframe)->buf_addr)
+ if (!pxmitframe->buf_addr)
return;
- hw_hdr_offset = TXDESC_SIZE +
- (((struct xmit_frame *)pxmitframe)->pkt_offset * PACKET_OFFSET_SZ);
-
- pframe = ((struct xmit_frame *)pxmitframe)->buf_addr + hw_hdr_offset;
+ hw_hdr_offset = TXDESC_SIZE + pxmitframe->pkt_offset * PACKET_OFFSET_SZ;
+ pframe = pxmitframe->buf_addr + hw_hdr_offset;
/* start to encrypt each fragment */
if ((pattrib->encrypt == _WEP40_) || (pattrib->encrypt == _WEP104_)) {
@@ -502,7 +500,7 @@ static void phase2(u8 *rc4key, const u8 *tk, const u16 *p1k, u16 iv16)
}
/* The hlen isn't include the IV */
-u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
+u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
{ /* exclude ICV */
u16 pnl;
u32 pnh;
@@ -519,17 +517,17 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
u8 *pframe, *payload, *iv, *prwskey;
union pn48 dot11txpn;
struct sta_info *stainfo;
- struct pkt_attrib *pattrib = &((struct xmit_frame *)pxmitframe)->attrib;
+ struct pkt_attrib *pattrib = &pxmitframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
u32 res = _SUCCESS;
- if (!((struct xmit_frame *)pxmitframe)->buf_addr)
+ if (!pxmitframe->buf_addr)
return _FAIL;
- hw_hdr_offset = TXDESC_SIZE +
- (((struct xmit_frame *)pxmitframe)->pkt_offset * PACKET_OFFSET_SZ);
- pframe = ((struct xmit_frame *)pxmitframe)->buf_addr + hw_hdr_offset;
+ hw_hdr_offset = TXDESC_SIZE + pxmitframe->pkt_offset * PACKET_OFFSET_SZ;
+ pframe = pxmitframe->buf_addr + hw_hdr_offset;
+
/* 4 start to encrypt each fragment */
if (pattrib->encrypt == _TKIP_) {
if (pattrib->psta)
@@ -1154,7 +1152,7 @@ static int aes_cipher(u8 *key, uint hdrlen, u8 *pframe, uint plen)
return _SUCCESS;
}
-u32 rtw_aes_encrypt(struct adapter *padapter, u8 *pxmitframe)
+u32 rtw_aes_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
{ /* exclude ICV */
/*static*/
@@ -1165,20 +1163,18 @@ u32 rtw_aes_encrypt(struct adapter *padapter, u8 *pxmitframe)
u8 *pframe, *prwskey; /* *payload,*iv */
u8 hw_hdr_offset = 0;
struct sta_info *stainfo;
- struct pkt_attrib *pattrib = &((struct xmit_frame *)pxmitframe)->attrib;
+ struct pkt_attrib *pattrib = &pxmitframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
/* uint offset = 0; */
u32 res = _SUCCESS;
- if (!((struct xmit_frame *)pxmitframe)->buf_addr)
+ if (!pxmitframe->buf_addr)
return _FAIL;
- hw_hdr_offset = TXDESC_SIZE +
- (((struct xmit_frame *)pxmitframe)->pkt_offset * PACKET_OFFSET_SZ);
-
- pframe = ((struct xmit_frame *)pxmitframe)->buf_addr + hw_hdr_offset;
+ hw_hdr_offset = TXDESC_SIZE + pxmitframe->pkt_offset * PACKET_OFFSET_SZ;
+ pframe = pxmitframe->buf_addr + hw_hdr_offset;
/* 4 start to encrypt each fragment */
if (pattrib->encrypt == _AES_) {
diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
index 46fe62c7c32c..bcc4d65cdcee 100644
--- a/drivers/staging/r8188eu/core/rtw_xmit.c
+++ b/drivers/staging/r8188eu/core/rtw_xmit.c
@@ -683,13 +683,13 @@ static s32 xmitframe_swencrypt(struct adapter *padapter, struct xmit_frame *pxmi
switch (pattrib->encrypt) {
case _WEP40_:
case _WEP104_:
- rtw_wep_encrypt(padapter, (u8 *)pxmitframe);
+ rtw_wep_encrypt(padapter, pxmitframe);
break;
case _TKIP_:
- rtw_tkip_encrypt(padapter, (u8 *)pxmitframe);
+ rtw_tkip_encrypt(padapter, pxmitframe);
break;
case _AES_:
- rtw_aes_encrypt(padapter, (u8 *)pxmitframe);
+ rtw_aes_encrypt(padapter, pxmitframe);
break;
default:
break;
diff --git a/drivers/staging/r8188eu/include/rtw_security.h b/drivers/staging/r8188eu/include/rtw_security.h
index ec6ecdb7bc98..4e6d4257b7ba 100644
--- a/drivers/staging/r8188eu/include/rtw_security.h
+++ b/drivers/staging/r8188eu/include/rtw_security.h
@@ -330,9 +330,9 @@ void rtw_secmicappend(struct mic_data *pmicdata, u8 *src, u32 nBytes);
void rtw_secgetmic(struct mic_data *pmicdata, u8 *dst);
void rtw_seccalctkipmic(u8 *key, u8 *header, u8 *data, u32 data_len,
u8 *Miccode, u8 priority);
-u32 rtw_aes_encrypt(struct adapter *padapter, u8 *pxmitframe);
-u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe);
-void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe);
+u32 rtw_aes_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe);
+u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe);
+void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe);
u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe);
u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe);
void rtw_wep_decrypt(struct adapter *padapter, u8 *precvframe);
--
2.32.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 2/3] staging: r8188eu: convert type of second parameter of rtw_*_decrypt()
2021-08-29 11:25 [PATCH 0/3] staging: r8188eu: clean up unnecessary type casts Michael Straube
2021-08-29 11:25 ` [PATCH 1/3] staging: r8188eu: convert type of second parameter of rtw_*_encrypt() Michael Straube
@ 2021-08-29 11:25 ` Michael Straube
2021-08-29 11:25 ` [PATCH 3/3] staging: r8188eu: remove unnecessary type casts Michael Straube
2021-08-30 0:16 ` [PATCH 0/3] staging: r8188eu: clean up " Phillip Potter
3 siblings, 0 replies; 5+ messages in thread
From: Michael Straube @ 2021-08-29 11:25 UTC (permalink / raw)
To: gregkh
Cc: Larry.Finger, phil, martin, fmdefrancesco, linux-staging,
linux-kernel, Michael Straube
Convert the type of the second parameter of the rtw_*_decrypt() functions
to struct recv_frame.
All callers of the functions cast the type to (u8 *) and in the functions
it is casted back to the original type. Changing the type of the second
parameter to struct recv_frame avoids these unnecessary casts and improves
readability.
Signed-off-by: Michael Straube <straube.linux@gmail.com>
---
drivers/staging/r8188eu/core/rtw_recv.c | 6 ++---
drivers/staging/r8188eu/core/rtw_security.c | 25 ++++++++++---------
.../staging/r8188eu/include/rtw_security.h | 6 ++---
3 files changed, 19 insertions(+), 18 deletions(-)
diff --git a/drivers/staging/r8188eu/core/rtw_recv.c b/drivers/staging/r8188eu/core/rtw_recv.c
index e082edfbaad8..019c5364905b 100644
--- a/drivers/staging/r8188eu/core/rtw_recv.c
+++ b/drivers/staging/r8188eu/core/rtw_recv.c
@@ -418,13 +418,13 @@ static struct recv_frame *decryptor(struct adapter *padapter, struct recv_frame
switch (prxattrib->encrypt) {
case _WEP40_:
case _WEP104_:
- rtw_wep_decrypt(padapter, (u8 *)precv_frame);
+ rtw_wep_decrypt(padapter, precv_frame);
break;
case _TKIP_:
- res = rtw_tkip_decrypt(padapter, (u8 *)precv_frame);
+ res = rtw_tkip_decrypt(padapter, precv_frame);
break;
case _AES_:
- res = rtw_aes_decrypt(padapter, (u8 *)precv_frame);
+ res = rtw_aes_decrypt(padapter, precv_frame);
break;
default:
break;
diff --git a/drivers/staging/r8188eu/core/rtw_security.c b/drivers/staging/r8188eu/core/rtw_security.c
index 5168159d8ae7..0836f38ca284 100644
--- a/drivers/staging/r8188eu/core/rtw_security.c
+++ b/drivers/staging/r8188eu/core/rtw_security.c
@@ -134,7 +134,7 @@ void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
}
-void rtw_wep_decrypt(struct adapter *padapter, u8 *precvframe)
+void rtw_wep_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
{
/* exclude ICV */
struct arc4context mycontext;
@@ -142,10 +142,10 @@ void rtw_wep_decrypt(struct adapter *padapter, u8 *precvframe)
u32 keylength;
u8 *pframe, *payload, *iv, wepkey[16];
u8 keyindex;
- struct rx_pkt_attrib *prxattrib = &(((struct recv_frame *)precvframe)->attrib);
+ struct rx_pkt_attrib *prxattrib = &precvframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
- pframe = (unsigned char *)((struct recv_frame *)precvframe)->rx_data;
+ pframe = (unsigned char *)precvframe->rx_data;
/* start to decrypt recvframe */
if ((prxattrib->encrypt == _WEP40_) || (prxattrib->encrypt == _WEP104_)) {
@@ -154,7 +154,7 @@ void rtw_wep_decrypt(struct adapter *padapter, u8 *precvframe)
keylength = psecuritypriv->dot11DefKeylen[keyindex];
memcpy(&wepkey[0], iv, 3);
memcpy(&wepkey[3], &psecuritypriv->dot11DefKey[keyindex].skey[0], keylength);
- length = ((struct recv_frame *)precvframe)->len - prxattrib->hdrlen - prxattrib->iv_len;
+ length = precvframe->len - prxattrib->hdrlen - prxattrib->iv_len;
payload = pframe + prxattrib->iv_len + prxattrib->hdrlen;
@@ -580,7 +580,7 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
}
/* The hlen isn't include the IV */
-u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
+u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
{ /* exclude ICV */
u16 pnl;
u32 pnh;
@@ -596,11 +596,11 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
u8 *pframe, *payload, *iv, *prwskey;
union pn48 dot11txpn;
struct sta_info *stainfo;
- struct rx_pkt_attrib *prxattrib = &((struct recv_frame *)precvframe)->attrib;
+ struct rx_pkt_attrib *prxattrib = &precvframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
u32 res = _SUCCESS;
- pframe = (unsigned char *)((struct recv_frame *)precvframe)->rx_data;
+ pframe = (unsigned char *)precvframe->rx_data;
/* 4 start to decrypt recvframe */
if (prxattrib->encrypt == _TKIP_) {
@@ -619,7 +619,7 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
iv = pframe + prxattrib->hdrlen;
payload = pframe + prxattrib->iv_len + prxattrib->hdrlen;
- length = ((struct recv_frame *)precvframe)->len - prxattrib->hdrlen - prxattrib->iv_len;
+ length = precvframe->len - prxattrib->hdrlen - prxattrib->iv_len;
GET_TKIP_PN(iv, dot11txpn);
@@ -1402,17 +1402,18 @@ static int aes_decipher(u8 *key, uint hdrlen,
return res;
}
-u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe)
+u32 rtw_aes_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
{ /* exclude ICV */
/* Intermediate Buffers */
int length;
u8 *pframe, *prwskey; /* *payload,*iv */
struct sta_info *stainfo;
- struct rx_pkt_attrib *prxattrib = &((struct recv_frame *)precvframe)->attrib;
+ struct rx_pkt_attrib *prxattrib = &precvframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
u32 res = _SUCCESS;
- pframe = (unsigned char *)((struct recv_frame *)precvframe)->rx_data;
+ pframe = (unsigned char *)precvframe->rx_data;
+
/* 4 start to encrypt each fragment */
if (prxattrib->encrypt == _AES_) {
stainfo = rtw_get_stainfo(&padapter->stapriv, &prxattrib->ta[0]);
@@ -1434,7 +1435,7 @@ u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe)
} else {
prwskey = &stainfo->dot118021x_UncstKey.skey[0];
}
- length = ((struct recv_frame *)precvframe)->len - prxattrib->hdrlen - prxattrib->iv_len;
+ length = precvframe->len - prxattrib->hdrlen - prxattrib->iv_len;
res = aes_decipher(prwskey, prxattrib->hdrlen, pframe, length);
} else {
res = _FAIL;
diff --git a/drivers/staging/r8188eu/include/rtw_security.h b/drivers/staging/r8188eu/include/rtw_security.h
index 4e6d4257b7ba..1fc1a4f30eec 100644
--- a/drivers/staging/r8188eu/include/rtw_security.h
+++ b/drivers/staging/r8188eu/include/rtw_security.h
@@ -333,9 +333,9 @@ void rtw_seccalctkipmic(u8 *key, u8 *header, u8 *data, u32 data_len,
u32 rtw_aes_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe);
u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe);
void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe);
-u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe);
-u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe);
-void rtw_wep_decrypt(struct adapter *padapter, u8 *precvframe);
+u32 rtw_aes_decrypt(struct adapter *padapter, struct recv_frame *precvframe);
+u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe);
+void rtw_wep_decrypt(struct adapter *padapter, struct recv_frame *precvframe);
void rtw_use_tkipkey_handler(void *FunctionContext);
#endif /* __RTL871X_SECURITY_H_ */
--
2.32.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 3/3] staging: r8188eu: remove unnecessary type casts
2021-08-29 11:25 [PATCH 0/3] staging: r8188eu: clean up unnecessary type casts Michael Straube
2021-08-29 11:25 ` [PATCH 1/3] staging: r8188eu: convert type of second parameter of rtw_*_encrypt() Michael Straube
2021-08-29 11:25 ` [PATCH 2/3] staging: r8188eu: convert type of second parameter of rtw_*_decrypt() Michael Straube
@ 2021-08-29 11:25 ` Michael Straube
2021-08-30 0:16 ` [PATCH 0/3] staging: r8188eu: clean up " Phillip Potter
3 siblings, 0 replies; 5+ messages in thread
From: Michael Straube @ 2021-08-29 11:25 UTC (permalink / raw)
To: gregkh
Cc: Larry.Finger, phil, martin, fmdefrancesco, linux-staging,
linux-kernel, Michael Straube
The field rx_data of struct recv_frame and the local variable pframe
both have type (u8 *). Remove unnecessary type casts to (unsigned char *).
Signed-off-by: Michael Straube <straube.linux@gmail.com>
---
drivers/staging/r8188eu/core/rtw_security.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/r8188eu/core/rtw_security.c b/drivers/staging/r8188eu/core/rtw_security.c
index 0836f38ca284..48f77c6cf43c 100644
--- a/drivers/staging/r8188eu/core/rtw_security.c
+++ b/drivers/staging/r8188eu/core/rtw_security.c
@@ -145,7 +145,7 @@ void rtw_wep_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
struct rx_pkt_attrib *prxattrib = &precvframe->attrib;
struct security_priv *psecuritypriv = &padapter->securitypriv;
- pframe = (unsigned char *)precvframe->rx_data;
+ pframe = precvframe->rx_data;
/* start to decrypt recvframe */
if ((prxattrib->encrypt == _WEP40_) || (prxattrib->encrypt == _WEP104_)) {
@@ -600,7 +600,7 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
struct security_priv *psecuritypriv = &padapter->securitypriv;
u32 res = _SUCCESS;
- pframe = (unsigned char *)precvframe->rx_data;
+ pframe = precvframe->rx_data;
/* 4 start to decrypt recvframe */
if (prxattrib->encrypt == _TKIP_) {
@@ -1412,7 +1412,7 @@ u32 rtw_aes_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
struct security_priv *psecuritypriv = &padapter->securitypriv;
u32 res = _SUCCESS;
- pframe = (unsigned char *)precvframe->rx_data;
+ pframe = precvframe->rx_data;
/* 4 start to encrypt each fragment */
if (prxattrib->encrypt == _AES_) {
--
2.32.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH 0/3] staging: r8188eu: clean up unnecessary type casts
2021-08-29 11:25 [PATCH 0/3] staging: r8188eu: clean up unnecessary type casts Michael Straube
` (2 preceding siblings ...)
2021-08-29 11:25 ` [PATCH 3/3] staging: r8188eu: remove unnecessary type casts Michael Straube
@ 2021-08-30 0:16 ` Phillip Potter
3 siblings, 0 replies; 5+ messages in thread
From: Phillip Potter @ 2021-08-30 0:16 UTC (permalink / raw)
To: Michael Straube
Cc: Greg KH, Larry Finger, Martin Kaiser, Fabio M. De Francesco,
open list:STAGING SUBSYSTEM, Linux Kernel Mailing List
On Sun, 29 Aug 2021 at 12:26, Michael Straube <straube.linux@gmail.com> wrote:
>
> This series removes unnecessary type casts from de/encrypt functions
> in core/rtw_security.c.
>
> Tested with Inter-Tech DMG-02 adapter connected to a CCMP network.
>
> Michael Straube (3):
> staging: r8188eu: convert type of second parameter of rtw_*_encrypt()
> staging: r8188eu: convert type of second parameter of rtw_*_decrypt()
> staging: r8188eu: remove unnecessary type casts
>
> drivers/staging/r8188eu/core/rtw_mlme_ext.c | 2 +-
> drivers/staging/r8188eu/core/rtw_recv.c | 6 +-
> drivers/staging/r8188eu/core/rtw_security.c | 61 +++++++++----------
> drivers/staging/r8188eu/core/rtw_xmit.c | 6 +-
> .../staging/r8188eu/include/rtw_security.h | 12 ++--
> 5 files changed, 42 insertions(+), 45 deletions(-)
>
> --
> 2.32.0
>
Dear Michael,
Looks good to me, built/run fine again, for whole series:
Acked-by: Phillip Potter <phil@philpotter.co.uk>
Regards,
Phil Potter
^ permalink raw reply [flat|nested] 5+ messages in thread